Crossovers in literature.
- Kevin J. Anderson's War of the Worlds: Global Dispatches is an anthology that crosses over H. G. Wells's The War of the Worlds with eighteen historical and fictional heroes, such as the characters from The Jungle Book and John Carter of Mars.
- Clive Barker's The Scarlet Gospels pits his Occult Detective, Harry D'Amour (from The Last Illusion) against Pinhead (from Hellraiser).
- Carrie Bebris's Mr. and Mrs. Darcy Mysteries: Elizabeth and Darcy travel around and solve crimes, meeting characters from Austen's other novels as they go.
- Ally Carter's novella "Double Cross" crosses over her The Gallagher Girls and Heist Society series.
- Michael Connelly's The Reversal crosses over Mickey Haller and Harry Bosch in the only book where they equally share the spotlight. Mickey has been asked to be a special prosecutor for a case- which he accepts on the condition that his half brother Bosch is allowed to be his investigator, and Mickey's ex-wife is allowed to be his co-council.
- Jim Davis's Garfield's Christmas Tales contains a story in which Garfield, during a Christmas trip to the Arbuckle family farm, pays a visit to the titular farm of U.S. Acres (which happens to be right next door to the Arbuckle farm) and helps Orson, Wade, and Roy win a snowball fight against Orson's brothers.
- Doctor Who:
- The Doctor Who novel, The Indestructible Man, features the Second Doctor and his companions, Victoria Waterfield and Jamie McCrimmon, in the mid-21st Century interacting with the characters from Gerry Anderson's "Supermarionation" TV series of the 1960s; Stingray, Thunderbirds, and Captain Scarlet, which were all on ITV at the same time that Doctor Who was on the BBC.
- The Doctor Who New Adventures novel All-Consuming Fire has the Doctor meeting the eponymous Sherlock Holmes.
- Win Scott Eckert's Crossovers: A Secret Chronology of the World documents a vast number of crossover stories that can all be demonstrated as fitting into the same world in this two-volume timeline.
- Neil Gaiman's Hugo-winning 2003 story A Study in Emerald places Sherlock Holmes in the world of H. P. Lovecraft.
- Harry Harrison's "The Fourth Law of Robotics": This story combines characters from Isaac Asimov's I, Robot and Harrison's The Stainless Steel Rat, and is set on Earth, where the majority of the Robot Series takes place.
- Howard Hopkins's Sherlock Holmes: The Crossover Casebook: An anthology of crossovers, where Sherlock meets characters from fourteen other franchises, such as Arsène Lupin, Lawrence Of Arabia, and Calamity Jane.
- Robert E. Howard's "Kings Of The Night": Advertised as a Bran Mak Morn story, it also features Kull's Kull of Atlantis. He and Bran team up against the Roman Legions invading Britain.
- Carolyn Keene's Super Mystery: Inspired by the success of The Hardy Boys/Nancy Drew Mysteries, several Nancy Drew/The Hardy Boys books paired the titular characters and ramped up considerable Unresolved Sexual Tension between Frank and Nancy.
- Rick Riordan:
- Two minor Percy Jackson and the Olympians characters, Drew and Lacy, appeared in the Serpent's Shadow, after two books worth of hinting that the two series took place in the same universe.
- As of the short story "The Son Of Sobek", Percy and Carter have met one another. Carter even left a hieroglyph on Percy's hand that could summon him should the need arise.
- Lin Haire Sargeant: The 1995 novel H: The Story of Heathcliff's Journey Back to Wuthering Heights crosses over the two Bronte sister classics Jane Eyre and Wuthering Heights.
- Star Trek: Federation justifies its crossover between Star Trek: The Original Series and The Next Generation by means of a Negative Space Wedgie.
- Project A75 is a crossover between all the stories that the author has written for the Looperverse, with the exception of The Adventures of a Sword.
- Stick Dog: The book "Stick Dog Crashes A Party" has Stick Dog and his friends sneak into the wedding of Stick Cat's family so they can get as much food from the wedding reception as possible.
- Stick Cat: The book "Two Cats To The Rescue" has Stick Cat and the family moving back to Goose's old neighbourhood. It's the neighbourhood that Stick Dog and his friends live in, so they all meet. Stick Dog & Co. help Stick Cat and Edith get Baby Millie home.
- Max & the Midknights: The Tower of Time: While looking through doors in the tower of time, Mary, Max, and Kevyn peer through one and see a classroom in which Nate is being chewed out by his teacher.
- Mercedes Lackey and Elisabeth Waters wrote a short story called A Dragon In Distress, in which Tarma and Kethry are compelled by Need to go through a portal into Waters' own fantasy setting, where they help a distressed female dragon whose adopted princess was kidnapped by a prince.
