So you're watching your favorite TV show, nothing seems unusual until a very familiar name is dropped. Bob McGee, from The Bob and Alice Adventures movie franchise? What's he doing in this random rom-com?
Character overlap is when a character in one series makes a crossover to another series. This is a casual way to tie these two shows together, and a technique used to help define a 'Verse.
Compare with Transplant and Company Cross-References, which encompasses other non-character references as well. See also Canon Welding. Not related to Significant Name Overlap.
Examples:
- Characters from The Day of Revolution and Family Complex have roles of varying sizes in Princess Princess. All three are written by Mikiyo Tsuda.
- Angel Links employees Valeria Vertone and Duuz Delax Rex appear in an episode of Outlaw Star. Similarly, Fred Luo, Clyde, and Iris all appear at various points in Angel Links.
- The Nasuverse. See below under Video Games.
- The Raildex. Characters in A Certain Magical Index, A Certain Scientific Railgun, and A Certain Scientific Accelerator cross over frequently since most of the action takes place in Academy City.
- Anything by CLAMP will have this. Tsubasa -RESERVoir CHRoNiCLE- took this idea and went further with it.
- Prior to Tsubasa the title characters of CLAMP School Detectives were probably the worst offenders. Two of them were also the lead characters of separate series (though one only lasted a single issue) and the third was a supporting character in Duklyon: CLAMP School Defenders. And this is before they put in a brief appearance in X1999.
- Isaac and Miria, lovable robbers from Baccano!, make cameos as members of the Dollars in Durarara!!. Since they're immortal, having them be in Durarara's time period is easy.
- Ken Akamatsu reused the one-shot character Mei from Love Hina in Negima! Magister Negi Magi.
- Eiji Ohtsuka's manga MPD Psycho and The Kurosagi Corpse Delivery Service both have a cop named Sasayama as a secondary character. Ohtsuka has confirmed that they are the same person and not just two people with a coincidental similarity of name.
- Fruits Basket creator Natsuki Takaya specifically mentioned that one of her post-Fruba series would have minor cameos from some of the Fruba cast, just to make it clear they're set in the same universe.
- The anime adaptation of AIR contains a brief cameo of three of the primary girls from Kanon. Amusingly, both the Japanese and English dubs kept vocal continuity between the cameo and the show proper. Note that this cameo does not happen in the original visual novel.
- Since most of Fujio Akatsuka's works take place in and around Akatsuka Ward, characters from his series would pop in and out of each others' stories every once in a while. While Osomatsu-kun's Matsuno brothers and Iyami were frequent targets of this, characters from Tensai Bakabon and Moretsu Ataro often made brief cameos as well.
- The 1988 Osomatsu-kun series was this in spades, with characters like Bakabon's Policeman and Ataro's Nyarome being cast mainstays.
- Many of Mochi's series and one-shot works have characters, places, and settings that overlap, indicating that they're all in the same fictional universe.
- Benjamin The Elephant and Bibi Blocksberg take place in the same city. While the main characters only occasionally team up, Intrepid Reporter Karla Kolumna and the Mayor Pain belong to the regular supporting cast of both series.
- This happened with The Confessions of Dorian Gray, creating a Shared Universe of sorts with Big Finish's Dark Shadows and Sherlock Holmes audio series. Holmes, voiced by Nicholas Briggs like in the audio series, appears in Confessions as does the Skin Walker Association, under a different name, from the Dark Shadows audios, while Alexander Vlahos reprises his role as Dorian Gray in Dark Shadows.
- This is what helped define the official Marvel and DC Universes back in the 50s and 60s.
- Obscure 1980s black-and-white comic Tales from the Aniverse featured a cat bounty hunter named Miss Chevious. Cartoonist Randy Zimmerman carried the character over into her own series, which runs in Flint Comix & Entertainment over 20 years later.
- Buffy the Vampire Slayer:
- The Season 8 comic Time Of Your Life crosses over with Fray, which takes place in the future. Buffy meets Melaka Fray and finds out that Willow is still alive and wants her dead. In season 9, Willow tries to keep this from happening.
- Melaka Fray also appears in the entire Buffy Season Twelve comic book series.
- Illyria from Angel shows up late in season 9.
- Illyria also appears in the entire Buffy Season Twelve.
- Recurring character Kathryn O'Brien from Garth Ennis's The Punisher MAX is implied to be the same person as the similar character Kathryn McAllister, who appeared in the final arc of his DC universe series Hitman.
- Zany To The Max has at least one crossover per season. All the crossovers are in this style (either the Warners enter into the other series, or characters from the other series enter the Animaniacs world).
- Played for laughs in a parody of Monsters, Inc. when Sekoila searches for a cat who has entered the Animaniacs world and misunderstands the Warners when they keep telling her about "South Dakota" (which happens to be the name of the cat).
Yakko: Excuse me, Sekoila, but have you seen South Dakota?
Sekoila: No, I haven't, Yakko. I've never even been there!- Interestingly, the Monsters, Inc. parody is in the third season, which consists of entirely crossover episodes!
- While it's all fanfiction, Jake English's Mysterious Theater of Scientific Romance from the Year 3000 has guest stars from Dinosaur Comics, Final Fantasy XIII-2, The DCU, Channel Awesome, My Little Pony: Friendship Is Magic and Pokémon. There's also an OC inspired by Cordless, and a Nasuverse OC.
- This is very common in MSTs featuring an original team rather than the original Mystery Science Theater 3000 team. Members of the crew can and do come from virtually any medium. For more examples, see the Refia forum.
- Red Fire, Red Planet and Bait and Switch overlap some characters with both each other and with the Star Trek Canon.
- Ba'woV, chief engineer of the IKS mupwI' in RFRP, is stated to have been an engineer on a freighter called the Shargrash when she first met her current husband Brokosh, a Lethean mercenary now in the employ of the Klingon Defense Force. The Shargrash was the freighter that the USS Bajor rescued from some Jem'Hadar in chapter five of B&S.
- Ensign Kate McMillan, a Mauve Shirt on the USS Bajor in B&S, is one of the viewpoint characters of RFRP.
- Will Riker and Deanna Troi from Star Trek: The Next Generation also appear. Will is now a fleet admiral working at Starfleet Command, while Deanna is the head of the Diplomatic Corps. She doesn't get any lines because she's still asleep in her only scene (it being three in the morning in San Francisco when Will was called in due to an imminent Klingon attack on Sol).
- Superwomen of Eva 2: Lone Heir of Krypton: This story's Asuka — who is Power Girl and later Supergirl — has showed up in other stories of the same author. Similarly, original characters — and versions of the canon ones — of his other stories have showed up in this, creating a Broad Strokes Shared Universe.
- Khaos Omega is known to do this to a much larger degree, with numerous versions of certain characters. A massive expansion to the Rainbow Angel harem with each specific sub-group having its own limitations even allows for multiples of them to be paired with Jet, the male leader of the harem in question.
- Disney Animated Canon:
- Frozen featured a cameo from Rapunzel and Eugene, taking place after Tangled.
- As described in the Western Animation folder, Hercules and Aladdin took place in the same universe due to a crossover between their animated shows. Although, it is largely not considered to be canon to the original animated movies because none of the TV animated series and Disney Toon movies are.
- Jay and Silent Bob famously reappear in all six films in The View Askewniverse — and also pop up in Scream 3. And some characters from different films are actually related to each other.
- Han from The Fast and the Furious films is also the very same Han from Better Luck Tomorrow according to Justin Lin.
- In the first live-action Transformers Film Series movie directed by Michael Bay, Travis Van Winkle plays a Jerk Jock named Trent DeMarco. The 2009 reboot of Friday the 13th, also produced by Michael Bay, has Travis Van Winkle play a Jerk Jock named Trent DeMarco. According to Word of God, they're the same character.
- Like the comics it's based on, the Marvel Cinematic Universe has several overlapping characters. Many of these are Early-Bird Cameo teases for later films. Not counting minor cameos, or the Avengers movies (and Captain America: Civil War) that have crossing over as a main selling point:
- Nearly every movie in Phase One has an appearance by either Nick Fury, Agent Coulson, or both. The exception is The Incredible Hulk, where Tony Stark represents S.H.I.E.L.D. in their place. Both Fury and Coulson also show up in Captain Marvel, after both had been absent from the films for several years.
- Black Widow first debuts as a supporting character in Iron Man 2, then later becomes a supporting character in Captain America: The Winter Soldier. Minor character Senator Stern also appears in both films.
- Howard Stark, introduced in the Iron Man films as Tony's late father, is a supporting character in the franchise's WWII-era adventures (Captain America: The First Avenger and the Agent Carter One-Shot and series).
- A major scene in Avengers: Age of Ultron involves the arms dealer Ulysses Klaue, who later carried over into Black Panther. This was a whole year before Black Panther himself was introduced in Civil War, and almost three before the Black Panther movie itself.
- Ant-Man includes a flashback scene with both Peggy Carter and Howard Stark, and Ant-Man gets in a fight with the Falcon.
- A series of viral videos promoting Phase Three movies feature Christine Everhart, the reporter from the first two Iron Man films. So far she's interacted with Scott Lang from Ant-Man, President Ellis from Iron Man 3, and Jackson Norris (via voice-over) from the All Hail the King One-Shot.
- While Captain America: Civil War is meant from the start to be a crossover movie, the appearance of Hulk character General (now Secretary) Thaddeus Ross is notable because it's been eight years since his last appearance and because he appears when the Hulk himself does not. It also has surprisingly heavy involvement by Black Panther characters like T'Challa, T'Chaka, and Everett Ross; a good two years before Black Panther came out.
- Tony Stark, Happy Hogan, and Pepper Potts from the Iron Man films appear in Spider-Man: Homecoming, since Tony is mentoring Peter in this continuity. Captain America also appears in government-made school PSAs as a Running Gag.
- Thor: Ragnarok is effectively a Thor/Hulk crossover, as both feature in the movie and it draws from comic storylines of both characters. Doctor Strange also appears for a scene.
- In addition to Fury and Coulson, Captain Marvel also has Ronan the Accuser and Korath the Pursuer from Guardians of the Galaxy.
- Spider-Man: Far From Home: Happy Hogan is still around, but now Nick Fury is stepping in to recruit Peter for Avenger duty; and he brings Maria Hill with him. "Fury and Hill" are actually body doubles for the real ones, as played by different overlap characters; Talos and Soren from Captain Marvel. A minor one-scene extra from the first Iron Man also returns as one of the many disgruntled ex-Stark employees in Mysterio's crew.
- Ricochet is implied to take place in the same universe as Die Hard (with which it shares a producer and scriptwriter) due to the appearance of journalist Gail Wallens, played by Mary Ellen Trainor, in both.
- A possibly downplayed example with "The Dan Band" who appear in both Old School and The Hangover as those two films were directed by Todd Phillips.
- Phillips also Creator Cameos in both films possibly being the same character though this has never been verified.
- Star Wars Expanded Universe:
- Hera Syndulla is a main character in Star Wars Rebels. Due to her rank as a General in the Rebel Alliance, this has allowed her to appear in other works including a mention in Rogue One, a major role in the Star Wars: Doctor Aphra comics, and a main role in Star Wars: Alphabet Squadron series.
- Saw Gerrera debuted in a Star Wars: The Clone Wars arc, intended by Word of God to be followed up in the unproduced Star Wars Underworld live-action series. Instead, his plot in Underworld was retooled into a major role in Rogue One, which branched off into appearances in Star Wars Rebels, Rogue One supporting material (including the Jyn-centric Rebel Rising novel), the Solo novelization, and Star Wars Jedi: Fallen Order.
- Darth Maul, debuting in The Phantom Menace, has since made major appearances in Star Wars: The Clone Wars and Star Wars Rebels, including a minor role in Solo and his own limited comic series, Star Wars – Darth Maul.
- General Hux's father, Brendol Hux, first appeared in Servants of the Empire before appearing with a major role in Star Wars: The Aftermath Trilogy and Star Wars: Phasma.
- Lone Wolf and its spin-off World of Lone Wolf:
- Madin Rendalim, master Healer from Durenor, appears both in Grey Star the Wizard and Fire on the Water, thus being one of the rare people having met both Lone Wolf and Grey Star.
- The Chaos-master is a villain both in Beyond the Nightmare Gate and The Prisoners of Time. Grey Star has to make an uncomfortable deal with him; Lone Wolf's encounter is much more straightforward.
- Acarya, the High Wizard of the Shianti, sends Grey Star on his quest, and is the one to welcome the New Order Grand Master and take the Moonstone from him.
- Several characters from L. Frank Baum's lesser-known books made appearances in Oz, most notably Cap'n Bill and his ward Trot, and a boy named Button-Bright who had a talent for ending up precisely where he wanted to be despite getting lost along the way.
- Agatha Christie does this a fair bit. For example, Inspector Japp of the Poirot series appears in the first Tommy and Tuppence book. Poirot's secretary Miss Lemon and friend Ariadne Oliver are both old associates of Mr. Parker Pyne, and Ariadne Oliver appears in The Pale Horse, which also featured the vicar's wife from the Miss Marple novel The Moving Finger. In Three Act Tragedy, Poirot teams up with Mr. Satterthwaite. A mysterious character who is only referred to as Mr. Robinson appears with Poirot in Cat Among the Pigeons, Miss Marple in At Bertram's Hotel, and Tommy and Tuppence in Postern of Fate; he also appears in Passenger to Frankfurt, which does not feature any of Christie's series detectives.
- The character Hoid appears in all of the works of Brandon Sanderson set in The Cosmere (Mistborn, Elantris, The Stormlight Archive and Warbreaker) to serve various roles, such as a beggar or a storyteller.
- Many, if not all, of the books written by Ted Dekker are in the same continuity, as one book references characters from seemingly unrelated books.
- One of Thomas Disch's stories made a brief reference to the horrible fate of the main character in his story "The Roaches".
- Although the Discworld is technically one series, readers tend to group the books according to which recurring protagonist is the focus, and certain said protagonists cross over briefly into other books. (In particular, Pterry has noted that it's very hard to set a novel in Ankh-Morpork without the Watch taking an interest.)
- One What Could Have Been moment: at one point Pterry considered that the various powers attending the Low King's coronation in Thud! would include the King and Queen of Lancre. We'd know they were Verence and Magrat, but to Vimes they'd just be a couple of royals he was briefly introduced to.
- One of Bret Easton Ellis's signature techniques: Clay, the protagonist of Less Than Zero, is a minor character in The Rules of Attraction; Patrick Bateman, a minor character in The Rules of Attraction, is the protagonist of American Psycho, and so on.
- The Henry Huggins books and its Sequel Series, Ramona Quimby are set in the same neighbourhood, so they share a couple characters.
- Stephen King will often make brief references to characters and events from previous books, especially if those books took place in Castle Rock, Maine.
- In John Masefield's adult adventure stories that begin with Sard Harker and his children's adventure stories that begin with The Midnight Folk feature several related families (as well as the fictional land of Santa Barbara, which appears or is mentioned in both). Sard Harker, the hero of the former, and Kay Harker, the hero of the latter, are presumably related (though the precise connection is not explicitly stated), with both Harkers coming from nautical families and living in the neighborhood of the titled Crowmarsh family. Abner Brown, the villain of the Kay Harker series, first appears as a henchman to the villain of Sard Harker.
- Brother Zachariah from The Mortal Instruments, is Jem Carstairs, who appears the way he does due to being unable to complete the entrance rituals because of the yin fen in his body.
- Kim Newman does this a lot. His Anno Dracula series, set in a world where all the vampire stories are true, and his Diogenes Club series, set in a world where pretty much every other sort of supernatural thing is true, are alternate timelines of each other and have a large overlap of regular characters. Jago, one of his standalone novels published before either of those, has the first appearance of several characters and locations that went on to feature in the Diogenes Club series. Jago also shares a minor character, the corrupt police constable Barry Erskine, with another standalone novel, Bad Dreams.
- Gino Fish appears in all three of Robert B. Parker's books series, Spenser, Jesse Stone and Sunny Randall representing The Mafia in Boston.
- Banjo Paterson's poem "The Man from Snowy River" namedrops the title character of another of his works, "Clancy of the Overflow." Clancy is also given a prominent role in the movie adaptation.
- And "Harrison, who made his pile when Pardon won the cup" is presumably the narrator and placer of the victorious bet in Paterson's "Pardon, the Son of Reprieve".
- Matthew Reilly had the character of Astro appear in supporting roles in his two main series, the Scarecrow books and the Jack West Jr. books. Scarecrow himself later appears in a Jack West Jr. book as a main character.
- Frequently occurs in the Tortall Universe by Tamora Pierce. In fact, it occurs in every sub-series. Alanna's crowd are significant characters in The Immortals, Daine is a friend of Keladry's in Protector of the Small, and the Trickster's Duet is about Alanna's daughter. Beka Cooper, due to being a prequel set 200 years before, restricts the overlapping characters to gods and immortals, most importantly the Cat. The Numair Chronicles is an interquel starring Numair, first introduced in The Immortals.
- S.M. Stirling's Nantucket series is confirmed to be connected to the author's Emberverse series.
- P. G. Wodehouse did this quite a bit, mostly by having characters in more than one series belong to the Drones Club or visit/make reference to Blandings Castle.
- Many of Daniel Pinkwater's books feature recurring minor characters, such as Rolzup the Martian High comissioner, or The Chicken Man, a black Hobo with a trained, performing chicken.
- Madeleine L'Engle wrote the Chronos and Kairos series (totaling fifteen books - sixteen if "The Anti-Muffins", a chapter excised from "Meet the Austins", later published separately, and eventually reincorporated into it in all editions from 1997 on, is counted), both of which feature appearances by Canon John Tallis and Zachery Gray, and also nine other novels that are connected via shared characters:
- Tallis appears in 1992's Certain Women.
- Members of the Renier family, aside from in the Chronos and Kairos sequences, appear in Ilsa (1946), A Severed Wasp (1982) (sequel to The Small Rain (1945)) and The Other Side of the Sun (1971).
- And Both Were Young (1949; later reissued with alterations in 1983) has Philippa "Flip" Hunter as the protagonist; Katherine Forrester owns one of her paintings in A Severed Wasp, and the latter book also includes the character of Mimi Oppenheimer, introduced in A Winter's Love (1957) (and identified as one of Polly O'Keefe's favorite authors in the Kairos novel A House Like a Lotus).
- A House Like a Lotus also includes Frank Rowan, older brother of Luisa Rowan, whose best friend is Camilla Dickinson, protagonist of the novels Camilla Dickinson (1951; later reissued with alterations as Camilla in 1965) and A Live Coal in the Sea (1996).
- Seanan McGuire's InCryptid and Ghost Roads take place in the same universe, and the ghost characters Rose Marshall and Mary Dunlavy appear in both. Rose guest-stars in the InCryptid short story "The Ghosts of Bourbon Street" (free on the author's website) and later appeared in book seven of the main series, Tricks For Free. Mary appears as a major character in Tricks for Free and the eighth book, That Ain't Witchcraft, and the Crossroads, the Greater-Scope Villain of Ghost Roads, is the main antagonist of those books. Rose also mentions other InCryptid characters in passing.
- In Eoin Colfer's The Supernaturalist, major character Stefan Bashkir is one of Artemis Fowl's aliases (though in this book he's clearly not Artemis). Phonetix, a company that has a rivalry with Myishi, had a rivalry with Jon Spiro's Fission Chips in The Eternity Code.
- Mercedes Lackey's Tarma and Kethry short stories were not initially in the same continuity as the Heralds of Valdemar books, but they didn't not fit and she did some Canon Welding. Tarma and Kethry's adventures take place well south of Valdemar and several decades before Talia (protagonist of the first Valdemar books) was born, so they don't meet, but Tarma and Kethry do briefly visit Valdemar and meet a Herald. Their granddaughter Kerowyn comes to Valdemar, meets Talia, and becomes a Herald herself in By The Sword.
- In Batman (1966), the Green Hornet and Kato showed up at times, for the window cameo usually. Likewise, the Batmobile is seen at one point in The Green Hornet. Both series had the same producer, William Dozier.
- Boston Public, Ally McBeal and The Practice had a crossover.
- Alan Shore from The Practice went to join the law firm in Boston Legal.
- Back when Jim Henson was alive and owned all of the The Muppets, Kermit the Frog provided this to the various Henson/Muppet productions. He was the main character on The Muppet Show, a major character on The Jim Henson Hour, a recurrer on Sesame Street, and host of specials such as Emmet Otter's Jug-Band Christmas . The various productions also had crossovers, though this doesn't happen as frequently now that the various parts of the former Muppet universe have been sold to different companies.
- Beverly Hills, 90210 begat Melrose Place which begat Models Inc. Characters like Jake from Melrose Place appeared on 90210 before Melrose Place began. Later Melrose Place characters appeared on Models Inc. (Amanda Woodward's mother and half-brother ran Models Inc.). Later, some of the original 90210 cast members returned for the reboot of 90210 and some of the original cast of Melrose Place returned for the reboot of that show as well.
- Steve Urkel of Family Matters fame has appeared in both Full House and Step by Step.
- Buffy the Vampire Slayer / Angel:
- The characters in both shows inhabited the same universe and crossed-over regularly. Angel, Cordelia, Wesley, Spike, and Harmony all started on Buffy and then became main characters on Angel. It's worth noting that they are the ones who end up with the most character development; all of them except for Harmony end their time in the Buffyverse very different from when they first appeared.
- Rumor has it, if Firefly had continued, at some point, the crew would have been passing a bar, one of the characters in a long black coat would have said, "Nothing ever bloody changes," before turning around to reveal himself as Spike.
- The Fray comics take place in the Buffyverse in the distant future, in which Buffy and the new slayers are long dead. Melaka Fray herself crossed into the Buffy Season Eight comic book during one arc.
- Melaka Fray also appears in the entire Buffy Season Twelve comic book series.
- Hercules: The Legendary Journeys had a spin-off in Xena: Warrior Princess, so this inevitable. While the leads occasionally ran into each other, the two shows featured a number of the same recurring characters, including Autolycus, Salmoneus, Ares, Aphrodite, Hades, and Dahak.
- Writers from both shows also experimented with this trope for minor villain Sisyphus. He first appears in "Death in Chains" (a Xena episode) and returns the following week in "Highway to Hades" (a Hercules episode). He dies in the latter episode, but returns in Xena's "Ten Little Warlords" (albeit played by a different actor this time).
- Young Hercules was set years in the past, so it served to explain how Hercules met already established characters, like Iolaus, Jason, and various Olympians. After the show was established, Lilith made a couple appearances as her adult self on Hercules: The Legendary Journeys.
- Characters from Cheers, including Norm, Cliff, Rebecca, and Frasier appeared on Wings, and later on the spin-off Frasier.
- Carla, Norm and Cliff were also in an episode of St. Elsewhere titled, amusingly enough, "Cheers". Carla has also appeared on the short lived Cheers spin-off The Tortellis which revolved around her ex-husband Nick, their brood of children and Nick's new wife Loretta most of which were recurring characters on Cheers.
- Dr. Roxanne Turner from St. Elsewhere showed up on an episode of Homicide: Life on the Street. Dr. Victor Ehrlich from St. Elsewhere appeared in the Homicide movie.
- Speaking of St. Elsewhere, related to this trope is the "Tommy Westphall Universe", a theory which posits that nearly 90% of all American television exists in a shared universe, which exists entirely inside the mind of Tommy Westphall, an autistic child character on St. Elsewhere who, in the series finale, is revealed to be looking into a snow globe and imagining the events of the television show. St. Elsewhere crossed over with many different shows, which themselves crossed over with, and spun off, many different shows, which themselves crossed over, etc, creating an interweaving "universe" that encompasses a good majority of American television.
- Richard Belzer has played Baltimore (later NY) PD detective John Munch on approximately a dozen different TV series.
- In addition to Belzer's example, Law & Order: SVU had Angie Harmon from the parent series consulting in the first series before they got their own, dedicated prosecutor. Whoever was playing the District Attorney in the parent series would also occasionally have an appearance.
- Characters from Stargate SG-1 and Stargate Atlantis regularly crossover.
- Several characters from SG-1 have also appeared on Stargate Universe more than once.
- McKay and Woolsey were both introduced as one-off antagonists in SG-1 before becoming regular characters on Stargate Atlantis. They both appeared in the Stargate Universe Season 2 episode "Seizure" to boot, making them the only Atlantis regulars bar Samantha Carter to appear in Universe.
- Characters from Friends and Mad About You have crossed over. Mostly it's been Phoebe and Ursula Buffet, identical twins both played by Lisa Kudrow. Kudrow originally appeared as Ursula on Mad About You, and when she was cast as Phoebe on Friends, the two characters were made into twins to explain their identical appearance.
- The Disney Channel did this with a triple crossover of some of their most popular shows, a mishmash called That's So Suite Life of Hannah Montana.
- Rare Panel Game example; before the final axing of its third part, Have I Got Buzzcocks All Over was an irregular Children in Need occurrence.
- Jack Harkness debuted in Doctor Who then got spun off into his own show, Torchwood. Similarly, Sarah Jane Smith originated on Doctor Who back in the '70s, had a brief spinoff called K-9 and Company, then returned to the revived series in the mid '00s before receiving her own spin-off, The Sarah Jane Adventures, taking K-9 along with her. Both of them returned for the 2-part fourth series finale of Doctor Who which also brought along two other characters from their own shows (Mr. Smith and Luke from SJA and Gwen and Ianto from Torchwood). Earlier Martha Jones had appeared on Torchwood for a story arc and later the Tenth Doctor visited Sarah Jane on SJA. Both characters then later reappeared for the Tenth Doctor's last story along with several other characters who had appeared throughout his tenure. The Eleventh Doctor appeared on SJA bringing along Jo Grant who was a companion to the Third Doctor just before Sarah Jane. Meanwhile, an early version of K-9 that had been Put on a Bus back in 1978 was featured in a non-BBC spin-off, K9.
- In the Cold Open of the episode "Seminar" from The Office (US), Michael Scott runs into David Brent, his counterpart from the original British series. David appears again in the season 7 finale "Search Committee" as one of the people auditioning to replace Michael as manager.
- The character Director Leon Vance appears in both NCIS and, its spin-off, NCIS: Los Angeles, being that he is the director of the Naval Criminal Investigative Service in CBS's NCIS franchise.
- Kensi from NCIS: Los Angeles made a guest appearance on the revival of Hawaii Five-0. And then NCIS: Los Angeles and Hawaii Five-0 did a two-way crossover where Callen and Sam came to Hawaii to prevent a black-market bioweapons buy, then Danno and Chin Ho went to L.A. to stop one of the involved parties from unleashing the bioweapon in question.
- The character Penelope Garcia is the technical analyst in both Criminal Minds and its spin-off, Criminal Minds: Suspect Behavior.
- The second season finale of Cougar Town features appearances by Ted Buckland and Abed.
- The second season finale of Community also features a brief blink and you miss it cameo of two characters from Cougar Town. Also, Abed references his being an extra on Cougar Town in Community.
- Which he actually appears in. As an extra.
- Oddly enough, while some actors who have appeared in creator Bill Lawrence's earlier series Scrubs have also appeared in Cougar Town, Ted is the only character that appears in both shows, and the show Scrubs exists in that universe. He even noticed how weird it was that some of the characters in Cougar Town looked like people he knew.
- The second season finale of Community also features a brief blink and you miss it cameo of two characters from Cougar Town. Also, Abed references his being an extra on Cougar Town in Community.
- Naturally, the different iterations of Star Trek feature cameos from different characters, and share recurring nemeses like Q and The Borg. Worf is particularly notable for being a main character on both Star Trek: The Next Generation and Star Trek: Deep Space Nine. O'Brien also counts; he started out as a nameless extra in TNG's pilot episode, becoming one of the most recurring characters on the show before being promoted to series regular on DS9.
- He's also an identically-named Identical Grandson of Colonel Worf in the last original Star Trek movie, allowing Worf to sorta be in three series.
- Every Star Trek series begins with a sendoff from someone from another (except the original, of course.) In Star Trek: The Next Generation McCoy visits the new Enterprise; in Star Trek: Deep Space Nine, Picard arrives at the station; in Voyager, we first meet Harry at Quark's bar. Of course, Star Trek: Enterprise is harder to do it with without Time Travel, but we do see a video of Zefram Cochrane, played by the same actor as in Star Trek: First Contact. And, Will Riker is actually in the holodeck playing out a historical recreation for the final episode (now considering this is a prequel series...)
- Even the films follow this: Star Trek: Generations includes several original cast members in the beginning and Kirk via basically time-travel passes the torch to Picard. While, in the 2009 reboot, Spock travels back in time and explains the origin of the villain.
- Mr. Drucker appeared on both Green Acres and Petticoat Junction, as his grocery store was frequented by both show's characters. The two shows often had characters visit each other regularly in the early seasons.
- Once Upon a Time (2011) and Once Upon a Time in Wonderland are set in the same 'verse and have had several one-way (OUAT-to-OUATW) crossovers. The crossover is set to happen the other was as ABC announced in April 2014 that at least one major character from the now-cancelled Wonderland is to join the regular cast of the parent series for the 2014-15 season.
- Ray Barone and Doug Heffernan were shown to be friends and often appeared on each other's shows.
- However, Kevin James originally played a completely different character (who also happened to be Ray's friend) on Everybody Loves Raymond.
- Karen Sisco appears in Justified, but due to rights issues uses the surname Goodall with the explanation that she's since married. She's played by Carla Gugino, who played her in the character's short lived television series.
- The TV branch of the Marvel Cinematic Universe has its own share of crossover characters:
- Agents of S.H.I.E.L.D. stars Coulson, who was established in the movies, and has seen appearances of various sizes from throughout the MCU:
- Nick Fury and Maria Hill make occasional appearances, as do Agent Sitwell (who appeared in various movies and One-Shot shorts) and Agent Blake (from the Item 47 One-Shot).
- Peggy Carter and a couple of the Howling Commandos from the first Captain America film show up in a flashback.
- Two episodes guest-star Thor's Lady Sif.
- Between his two movie appearances (Captain America: The Winter Soldier's mid-credits scene and the opening of Avengers: Age of Ultron), high-ranking HYDRA scientist Dr. List appeared on Agents of S.H.I.E.L.D. as a major enemy; his boss Baron Strucker also got name-dropped regularly during that same period.
- One of the World Security Council members from The Avengers is a major character in Season 3, and is revealed to be a leader of HYDRA. President Ellis from Iron Man 3 also makes recurring appearances in Season 3.
- Various WWII-era Captain America characters have carried over to Agent Carter (both the TV series and the One-Shot short film that preceded it): Peggy Carter (of course), Howard Stark, Dum-Dum Dugan, and Arnim Zola. Anton Vanko from Iron Man 2 also briefly appears.
- The Netflix shows share a number of characters among themselves, and The Defenders (2017) is its Avengers equivalent bringing them all together:
- Claire Temple serves a similar role that Coulson once did in the movies, appearing in a supporting role in all the various shows (except for The Punisher).
- Iron Fist (2017) villain Madame Gao first appeared two years earlier as one of Wilson Fisk's associates in Daredevil (2015).
- Luke Cage appeared in Jessica Jones (2015) before he got a series of his own. His late wife Reva also appeared in flashbacks in both shows.
- As of the second season of Daredevil, Marci has gotten a new job at Hogarth, Chao and Benowitz from Jessica Jones, and Jeri Hogarth personally shows up later to hire Foggy as well. Hogarth also appears in Iron Fist.
- Luke Cage (2016) includes Turk Barrett, Ben Donovan, and Blake Tower from Daredevil, and a voice-only appearance by Trish Walker from Jessica Jones via her radio talk show.
- Frank Castle was a major character in Season 2 of Daredevil before being spun off into his own show. Karen Page, Mitchell Ellison and Brett Mahoney also follow Frank into The Punisher. Claire would have been included as well, but the writers couldn't figure out a good way for her to get involved.
- Another Iron Fist (2017) one: Danny Rand crosses over to Luke Cage (2016) season 2, resulting in the MCU take on Heroes for Hire.
- Connecting to the wider MCU, Carl "Crusher" Creel plays notable parts in both Agents of S.H.I.E.L.D. and the backstory of Daredevil, though he doesn't appear onscreen in the latter. Daredevil also has the Dogs of Hell biker gang in Season 2, which originated in an episode of Agents, though these are obviously different chapters.
- Agents of S.H.I.E.L.D. stars Coulson, who was established in the movies, and has seen appearances of various sizes from throughout the MCU:
- George Jefferson, from All in the Family and The Jeffersons, made a few appearances in The Fresh Prince of Bel-Air, including a brief but important role in that show's series finale where he purchases the Banks' house when they decide to move out.
- The Arrowverse characters cross over frequently. Sometimes it'll be a big Crisis Crossovers, featuring lots of characters from each series, but other times it'll be just one character making a cameo or guest spot on a different show (Felicity from Arrow attended Iris's bachelorette party on The Flash (2014), Barry Allen from The Flash (2014) accidentally ran through a portal to Supergirl (2015)'s universe, John Constantine made a guest appearance on Arrow following his own show's cancellation, and eventually joined the main cast of Legends of Tomorrow, etc.)
- The Nanny:
- "The Bobbi Fleckman Story" had Fran Drescher playing the titular Bobbi Fleckman, her character from This Is Spın̈al Tap.
- "The Reunion Show" had Ray Romano appearing as Ray Barone from Everybody Loves Raymond.
- The National Wrestling Alliance wasn't the first, or even the second wrestling body to proclaim a World Heavyweight Championship, but it turned the world title belt into a powerful marketing tool by establishing a larger alliance of wrestling promotions around the world than ever before seen and sending the world champion through each of them to defeat local competitors and legitimize himself, each promotion having some say in who would hold the belt. The NWA has/had several other world champions to.
- Bad Ass Translate Trading(BATT), the most visible sign of the All Japan\New Japan working agreement of 2000-02, as it was a Power Stable containing members of both promotion's locker rooms and thus was the most constant source of overlap.
- Ring of Honor officially recognized SHIMMER's champions as its own "women of honor" and The World Wrestling Network established itself as such by having the Full Impact Pro Heavyweight Champion defend his belt at ROH events.
- The Allied Independent Wrestling Federations each have their own separate title belts but all recognize a specific group of champions who represent them all. Even though Ring Wars Carolina is not an official member of the AIWF, they still did away with their own women's championship (in favor of a No Limitz belt anyone could challenge for) and hosted AIWF women's championship matches instead, including the match to decide the very first women's champion.
- Pro Wrestling International, fearing the end of pro wrestling as we know it, got the idea to send its champions to independent promotions in Canada and Europe, to get them recognized by them and promote collaboration, realizing in the current climate, competition wasn't always necessary, or even best for business.
- The World Wrestling League titles have been defended in promotions ranging from The Dominican Republic to Mexico to Bolivia and occasionally it works the other way around, with NRW LL, WWC and all around Puerto Rican star Glamour Boy Shane being acknowledged as such in TNA, despite being a lowly referee there or its talent's TNA exploits being openly referred to during their AAA or CMLL appearances.
- RPGs are well known for cameo characters making appearances in different games by the same developers, though these characters don't necessarily indicate that the games take place in the same universe, and are often a sort of internal Shout-Out.
- Cless and Arche from Tales of Phantasia appear in Tales of Destiny, as does Clemente from Tales of Destiny.
- Chelsea from Tales of Destiny appears in Tales of Eternia.
- Tales of Hearts raises this to a gameplay element; scattered through the game are artifacts that let you summon characters from every previous Tales game to perform an attack for you in battle, from Arche to Ruca and Iria, and Caius and Rubia from the otherwise all but disowned Tales of the Tempest. As well as other characters from Bandai Namco games, like Gil, Klonoa, and KOS-MOS.
- Gilgamesh from Final Fantasy V makes appearances in other Final Fantasy games, such as VIII, IX, XI, XII, Revenant Wings, XIII-2, Type-0, XIV, and XV. And, retroactively, I and VI via their Game Boy Advance remakes. And something of a Big-Lipped Alligator Moment in The Very Definitely Final Dungeon of The After Years, which suggests every FF game with Crystals shares an origin through the game's Big Bad. There's the unspoken implication that he's a Dimensional Traveler, and that it's actually the same Gilgamesh in (nearly) every appearance. Curiously, Type-0 appears to be his origin story, or at least a glimpse at his life prior to V.
- Balthier from Final Fantasy XII and Luso from Final Fantasy Tactics A2 appear in the remake of Final Fantasy Tactics. Several FFXII characters also appear in A2, this time appearing to indicate that the two games do take place in the same universe. Same universe, same planet, even the same kingdom, for the most part. Ivalice, it's called. Vagrant Story's in there, too.
- Dissidia Final Fantasy appears to indicate that all the FF games are part of the same multiverse, if rather shakily. Among other things it makes explicit what fans had long speculated: that it really is the same Gilgamesh showing up in more than half the games of the series, as his exit from FFV resulted in him dimension-hopping. According to the rules of the conflict in Dissidia, his banishment to the Void at the hands of Exdeath has left Gil without a world to call his home.
- Bleu/Deis appears in several Breath of Fire games. It's the same Deis in every game where she appears, not just a Shout-Out cameo, as she's an immortal goddess and the sister of the franchise Big Bad, Tyr/Myria.
- Weak Warrior, Dragon Storm, and Kingdom Wars characters overlap.
- MonTowers ~Legend of Summoners~ and MonTowers II characters overlap.
- Anime Arcade, Cyanity, Anime Gacha! and Gacha World characters overlap.
- Gabrielle Celeste and the Ethereal Queen appear in all the Star Ocean and Valkyrie Profile games (made by tri-Ace). In addition, Lenneth and Freya from VP1 appear in Star Ocean: Till the End of Time; Puffy appears in every Star Ocean installment up to The Last Hope; Ruddle/Raddle the Traveler appears in all five main Star Ocean games; Dirna Hamilton and Solon Solute from SO3 appear in VP2; and Welch from SO3 appears in the remakes of SO1 and SO2 as well as SO4 and SO5 after, plus the mobile RPG Anamnesis.
- There's only a few Nippon Ichi games that don't feature crossover cameo appearances, most of them being recruitable, and the list only continues to grow. In fact, Asagi, who debuted as an Early-Bird Cameo for a cancelled game, lives on solely as a cameo. She'd had a 100% attendance record every since.
- The Shin Megami Tensei series has included many crossovers, from the main character from Shin Megami Tensei if... appearing in Persona and Persona 2, and Raidou appearing in the rerelease of Shin Megami Tensei: Nocturne (in place of Dante) included with the special edition of Raidou Kuzunoha 2. More recently, Vincent, the main character of Catherine, made a cameo in Persona 3 Portable.
- Castle of Shikigami: Nigi Gorgeous Blue from Gunparade March appears in Castle of Shikigami II, and Reika from Time Gal appears in Castle of Shikigami III.
- While the older Ace Combat games were unambiguously set in the same Constructed World, their storylines were so self-contained that they could have just as well been taking place in parallel universes. However, a few overlapping characters linked the storylines together.
- The Monsta and Mighta enemies from Bubble Bobble also appeared in the earlier Taito game Chack'n Pop.
- NYPD Detective Sam Durkin first appeared in The Shivah, he has since gotten a more expanded role in The Blackwell Series. As Unavowed takes place in the same universe, it also sees him appearing in a minor role.
- The core series Pokémon games set in different regions (except for Kanto and Johto, which are paired due to the former being fully available in the latter's games) traditionally share very few characters, but there are exceptions:
- The main character from the Kanto games, Red, and his rival, Blue, not only appear as the strongest Trainer in the game and a Gym Leader, respectively, in Generation II, but also as bosses of the Battle Tree in Generation VII's Alola region.
- The Pokémon World Tournament from Pokémon Black 2 and White 2 contains a Champions Tournament, featuring all Champions from all Generations up to that one (Gen V), including the aforementioned Red, and serveral Leaders Tournaments, featuring all Gym Leaders from a specific region or, in the case of the World Leaders Torunament and the Rental Master Tournament, all regions.
- Professor Oak from Kanto doesn't only appear in Generation II, but also has a brief cameo in Generation IV. Also, his cousin Samson is introduced in Alola.
- Jasmine, the Olivine City Gym Leader from the Johto games, appears briefly at Sinnoh's Sunyshore City in the Generation IV titles and can also turn as an opponent in the Super Contests held at Hearthome City. In return, Crasher Wake, the Pastoria City Gym Leader, makes an appearance in the Generation IV remakes of Gold and Silver, HeartGold and SoulSilver, at both the Celadon Department Store and Route 47. A conversation between Jasmine and Erika of the Celadon City Gym in HG/SS places Jasmine's cameo in Sinnoh after the main events of the Johto games.
- Sinnoh's Champion Cynthia also appears in HeartGold/SoulSilver if you take Arceus to the Ruins of Alph, whereupon an event will trigger and transport the player to the Sinjoh Ruins. She'd then appear in Black/White and their sequels at Undella Town, camping out at a villa owned by Caitlin (see below).
- Speaking of Champions, Steven Stone, the (former) from Hoenn region Champion, makes an appearance at Pewter City during the postgame of HeartGold/SoulSilver.
- In both the Kanto remakes and the original Hoenn games, it is mentioned that Brawly, the Dewford City Gym Leader from Hoenn, and Bruno, the Elite Four member from Kanto, used to train together in Kanto before Brawly moved to Hoenn.
- Caitlin first appears as the head of the Battle Castle in the Battle Frontier of Pokémon Platinum (set in Sinnoh) and the Johto remakes. She later reappears as a member of the Elite Four in the Unova games.
- Since his introduction in Platinum, international police member Looker has reappeared in every main series game (remakes included) up until Gen VII's Let's Go!
- Both Grimsley of the Unova Elite Four and Colress of Team Plasma appear in Sun/Moon, with Grimsley indirectly assisting the player's infiltration of Team Skull's HQ in Po Town by registering a Sharpedo as one of the player's Ride Pokémon. Ultra Sun/Ultra Moon would then expand Colress's role by having him be one of the scientific minds the Ultra Recon Squad reached out to for help with the approaching threat of Necrozma as well as playing a part in the defeat of Ghetsis and Team Rainbow Rocket during Episode RR.
- Frontier Brain Anabel from Pokémon Emerald, set in Hoenn, later reappears as Looker's colleague in Alola. What makes this example an interesting one is that the games involving Mega Evolution as a gameplay mechanic (i.e. Gen VI and onward) are all but stated to exist in an Alternate Universe from the games that don't... and it's heavily implied, due to her status as a "Faller" and her hazy memories of her past life, that the Anabel seen in these games is the actual Anabel from Emerald, not her Mega Timeline counterpart.
- Professor Burnet from Pokémon Dream Radar (released during Gen V as a companion to the Black/White titles) reappears in Generation VII and is revealed to be married to Alola's Professor Kukui.
- Dexio and Sina, Professor Sycamore's assistants in Pokémon X and Y, reappear in (Ultra) Sun/Moon, investigating the appearance of Zygarde in Alola and later explaining to the player the mechanics of Mega Evolution while providing them with a Key Stone and Mega Stone of their own.
- Similar to the Pokémon World Tournament, the aforementioned Battle Tree in Alola features several notable Trainers from previous games as potential opponents or partners in Double Battles. In addition to several names listed above (Red, Blue, Anabel, Cynthia, Grimsley, Colress, Dexio, Sina), Wally, the Friendly Rival from Hoenn, also turns up here.
- A handful of overlapping characters is all that holds the Type-Moon multiverse together (the convoluted magic laws aside): Cool Old Guy Zelretch plays a large role in the backstory of Tsukihime and makes a cameo appearance in Fate/stay night. His unique True Magic allows him to travel through the multiverse, and to create devices allowing others to do the same. Cool Big Sis Touko Aozaki is a major character in The Garden of Sinners, is mentioned briefly in Fate, and her sister Aoko appears in Tsukihime and is the protagonist of Witch on the Holy Night (which Touko also appears in).
- When Voltage Entertainment USA localized My Sweet Bodyguard into To Love & Protect, Japanese Prime Minister Hiraizumi was adapted into President Robertson and his bodyguards Daichi Katsuragi and Subaru Ichiyanagi into Secret Service agents Chadwick McGrew and Edgar Morton. Robertson subsequently appears in a major supporting role in the Voltage USA original game Queen's Gambit, with Chadwick and Edgar in minor roles. It's not clear if this is a case of shared continuity, alternate continuity, or simply recycling of convenient existing character assets.
- The Midnight Crew appeared in the tenuously canonical Fan Donation section of Problem Sleuth before having an intermission to themselves in Homestuck, which was revealed at the end to have storyline relevance with the Crew being exiles from the Trolls' session, and their rival gang.
- While their stories take place in different settings, the authors of Never Satisfied and Riverside Extras loaned each other characters from their respective works:
- Lucy Marlowe had a guest role in a chapter of Riverside Extras, before their own comic started.
- Several of Magister Lapointe's proxies in Never Satisfied are Riverside cameos, including Ophelia, Derry, Siobhan, and Dr. Brandt. Lapointe herself was initially meant to be a Riverside character (Ma Oceana), but ended up assuming a larger role as the story progressed and was subsequently retconned into a separate character to avoid both comics sharing a main antagonist.
- Peritale and Life of Melody take place in a shared setting. The main characters of the latter (Razzmatazz, Bon, and Melody) appear in a brief scene in the former. Marie and Mr. Lefèbvre, the main characters of The Well by the House on the Hill from the same author, appear in a supporting role in Peritale, though the comics don't share a setting or continuity.
- The Angry Video Game Nerd: PatTheNESPunk appears in Episode 104. Bullshit Man appears in Episode 113. Board James appears in Episodes 115 and 137.
- Board James: The Angry Video Game Nerd appears in Episode 25.
- Channel Awesome: The Angry Video Game Nerd appears in TGWTG Year One Brawl, while Board James appears in Kickassia.
- Empires SMP Season 2:
- Oli's Afterlife SMP finale episode segues directly into his first Empires Season 2 episode.
- Shelby's Empires Season 2 finale confirms that she's the same character as the Storm Witch from the WitchCraft SMP, just about ten years younger.
- InTheLittleWood has established that his "Datastream Defender" V-Tuber lore characters from the Rats SMP and the Pirates SMP are the same character, and has stated that his Life SMP "Eyes and Ears" continuity is connected to his V-Tuber lore, thus connecting that series' iteration of him as well.
- The Tales from the SMP episode "The Haunted Mansion" confirms that the Connor and Schlatt from the Dream SMP are the same characters from SMPLive.
- Probably the most famous practitioner of this in animation is Hanna-Barbera. During The '70s and into The '80s, H-B loved crossing over its own properties as much as possible.
- Scooby-Doo was an absolute magnet for this. Characters from H-B's adventure series (original and licensed) showed up — including (but not limited to) Jeannie, Speed Buggy, Dynomutt, and Josie and the Pussycats. The Laff-A-Lympics also revolved around this concept.
- An episode of Scooby-Doo! Mystery Incorporated poked fun at this tendency with Scooby teaming up with Captain Caveman, Jabberjaw, Speed Buggy, and Mudsy/the Funky Phantom. However, it would turn out to be dream and none of them exist in the world of Mystery Incorporated except as fictional characters (or completely made up by Scooby's imagination, in the case of Mudsy and the Funky Phantom crew).
- Yet another Mystery Inc. episode featured an extended cameo of Blue Falcon and Dynomutt... only this time not Played for Laughs.
- During Scooby-Doo's period of near-total inactivity (1991-1998), the gang crossed over with Johnny Bravo in "Bravo-Dooby-Doo".
- The Scooby-Doo! Team Up comics featured numerous crossovers between classic Scooby-Doo and numerous DC Comics characters in their general depictions, although one issue had a specific crossover with the Teen Titans Go! show.
- Scooby-Doo and Guess Who? features numerous crossovers, again with other Hanna-Barbera properties like The Funky Phantom and DC Comics characters (with an implication that these DC heroes are their Justice League Action incarnations).
- Scooby-Doo! & Batman: The Brave and the Bold is a crossover between the Scooby-Doo Direct-to-Video Film Series and Batman: The Brave and the Bold. The latter had already had guest star appearance from Mystery Incorporated in their classic incarnation as well.
- At least three of H-B's Made-for-TV Movies crossed Yogi Bear over with characters from The Huckleberry Hound Show along with some of their other cartoon series with similar design aesthetics.
- Similarly, a Space Ghost cliffhanger was resolved with the aid of the company's less-remembered Moby Dick interpretation.
- The Jetsons Meet the Flintstones exists. Did we mention Hanna-Barbera loved this trope?
- Long after the studio was absorbed into the Time-Warner empire, the trend continues:
- The cast of Harvey Birdman, Attorney at Law is made up largely of classic (often very obscure) Hanna-Barbera characters, and the litigants are very often from the well-known Hanna-Barbera series.
- OK K.O.! Let's Be Heroes, being one giant love letter to Cartoon Network's old Hanna-Barbera originals, also gets in on the action. One episode even brings in Captain Planet to help stop an eco-terrorist plot, and another brings back the Grimwood Girls from Scooby-Doo and the Ghoul School as Enid's childhood friends. Hanna-Barbera aside, the show also provided a Fully Absorbed Finale to series creator Ian Jones-Quartey's previous work, RPG World.
- Scooby-Doo was an absolute magnet for this. Characters from H-B's adventure series (original and licensed) showed up — including (but not limited to) Jeannie, Speed Buggy, Dynomutt, and Josie and the Pussycats. The Laff-A-Lympics also revolved around this concept.
- Lilo & Stitch: The Series leaned into the Running Gag of Stitch meddling in other Disney franchises, crossing over with Kim Possible, American Dragon: Jake Long, Recess, and The Proud Family on different occasions.
- G.I. Joe: A Real American Hero, Inhumanoids, Jem, and The Transformers share the journalist Hector Ramirez, leading to speculation of a shared universe. In turn, in the third season of The Transformers (which took place 20 years into the future), elderly versions of Flint and Cobra Commander from G.I. Joe: A Real American Hero made appearances.
- One episode of Hercules: The Animated Series involved a crossover with the cast of Aladdin: The Series.
- DuckTales (1987) and Darkwing Duck have Launchpad McQuack in common as a main character, and Gizmo-Duck as a notable recurring one. Darkwing also saw the occasional cameo from Flintheart Glomgold, the Beagle Boys, and Magica De Spell.
- Ace Ventura: Pet Detective: Stanley Ipkiss from the animated adaptation of The Mask makes an appearance in the second season finale. It's a sequel to a Mask episode that features Ace and his pet monkey Spike.
- Animaniacs:
- The show begat Pinky and the Brain, which became Pinky, Elmyra & the Brain with the inclusion of Elmyra from Tiny Toon Adventures. Elmyra also appeared in an early episode, "Lookit the Fuzzy Heads", where she joins the Warners in one of Dr. Scratchensniff's therapy sessions.
- Wakko and Brain both appear in an episode of Freakazoid!, where they all get into an argument over who Steven Spielberg likes best. Answer? He doesn't know who any of them are.
- Bugs Bunny and Daffy Duck make cameo appearances in "The Warners' 65 Anniversary Special" and "Back in Style", while Wile E Coyote And The Roadrunner appear in "Little Old Slappy from Pasadena".
- A character appears in the finale of Camp Lazlo, and though they're not namechecked, they're heavily implied to be a Lawyer-Friendly Cameo of Heffer Wolfe from Rocko's Modern Life. A Running Gag associated with them (being mistaken for a cow) comes up in their appearance to highlight this.
- Ben 10:
- Generator Rex had a crossover special with fellow Man of Action Studios Ben 10: Ultimate Alien, where it turned out Generator Rex and Ben 10 exist in the same multiverse. Ben 10: Omniverse would also feature a guest star appearance from the Secret Saturdays (albeit redesigned and with different voice actors), whose show had been over for a couple of years by the time of this crossover.
- Ben 10 (2016) had a Crisis Crossover with several other Cartoon Network shows, explained as being other universes (including the aforementioned Generator Rex and The Secret Saturdays in Crossover Cameo appearances). Ben teamed up with Steven Universe's Garnet, Teen Titans Go!'s Raven, and OK K.O.! Let's Be Heroes's K.O.
- Demona from Gargoyles would have appeared in an episode of the cancelled Atlantis: The Lost Empire animated series. However, Word of God clarifies that the two stories merely intersect here and otherwise don't share the same universe, due to his own plans for the city of Atlantis in Gargoyles that isn't based on the portrayal in the Atlantis universe.
- Star Trek: Lower Decks, being an animated installment of the Star Trek franchise, is rife with crossovers from other entries, allowing certain characters and concepts to appear here without much worry about things like appearance. Even more so, it allows us to see what they've been up to since their last (chronical, as the show takes place starting in 2380, a mere year or two after Star Trek: Nemesis and Star Trek: Voyager) appearance, such as Riker and Troi on the Titan or Kira and Quark on Deep Space Nine.