- Who Framed Roger Rabbit crossed over Disney characters with characters from Warner Bros. and other studios, saying that they all co-existed with humans as actors in Hollywood, and that they all hail from "Toontown", which seemed to be half Los Angeles and half Alternate Universe. That said, the actual plot mostly revolves around characters specific to the movie (and the book on which it was loosely based), with the pre-existing characters mostly being cameos.
- The Monster Squad had Dracula as the Big Bad who controlled all of the other classic movie monsters: Frakenstein's Monster, the Wolf Man, the Creature from the Black Lagoon and the Mummy. There is also a cameo by Abraham Van Helsing.
- The Area 52 scene in Looney Tunes: Back in Action involved the heroes facing off against Marvin the Martian, who led a group of sci-fi aliens which included a Triffid plant, the eponymous Robot Monster, the mutant from This Island Earth and even freaking Daleks!
- Many Seltzer and Friedberg works, such as Epic Movie and Disaster Movie, could be considered Massive Multiplayer Crossovers, insofar as they feature many characters and plot elements (or weak parodies thereof) from recent movies and mash them all together. By all rights, this really should produce something worth watching on some level.
- A version of this in Star Trek: Generations, which featured the captains of two Enterprises from completely different eras (Kirk and Picard) in the same film. Star Trek has done this numerous times, if you consider the different series separate entities of the same intellectual property.
- Van Helsing, which features the eponymous monster hunter battling Dracula, a werewolf, Frankenstein's Monster, Igor and Mr. Hyde.
- Done with toys in The Indian in the Cupboard.
- Mega Monster Battle Ultra Galaxy Legends The Movie fuses many Ultra kaiju from many different series into one movie.
- And with horror-movie creatures in the Waxwork movies.
- Toy Story features many toys from rival companies as major or minor characters including Mr. Potato Head, Barbie, and LEGO among many others. (And probably some expies too.)
- The Avengers series serves as this for the Marvel Cinematic Universe.
- Avengers: Infinity War takes up to eleven as it features not just the Avengers, but pretty much all superheroes from Marvel Cinematic Universe film series: including the Guardians of the Galaxy, Doctor Strange and Wong, Black Panther and other Wakandans, Asgardians, and Spider-Man.
- In 1959 a movie was released called Alias Jessie James starring Bob Hope, who was a big fan of TV westerns; he used his clout to include characters from nine different shows in what would turn out to be the first of three Western massive multiplayer crossovers. People appeared in that movie from The Lone Ranger, The Gene Autry Show, Annie Oakley, Davy Crockett, The Life And Legend Of Wyatt Earp, Gunsmoke, Wagon Train, The Roy Rogers Show and Maverick.
- In the 40th Anniversary OOO, Den-O, All Riders: Let's Go Kamen Rider has all of the main riders from Kamen Rider #1 to Kamen Rider OOO.
- The Shrek films do this to fairy tale characters.
- Wreck-It Ralph does this with arcade video game characters.
- The LEGO Movie features Batman, Superman, Wonder Woman, Green Lantern, the Flash, Gandalf, Dumbledore, Milhouse, Speed Racer, the Teenage Mutant Ninja Turtles, Han Solo, Chewbacca, C-3P0, Lando...and that's not including characters from LEGO's own themes!
- In the same vein, in The Lego Batman Movie, the Joker abandons Batman's usual Rogues Gallery to create his own made of the villains he finds in the Phantom Zone, featuring King Kong, the Eye of Sauron, the Wicked Witch and her Flying Monkeys, Lord Voldemort, Agent Smith, the Gremlins, and ... British Robots! (Ask your nerd friends). Interestingly, the film makes no mention of General Zod, who Superman sends to the Phantom Zone earlier in the movie. Equally strange is the film's inclusion of Agent Smith, the Wicked Witch and The Gremlins, who had only been available previously in relation to LEGO Dimensions, Lord Voldemort, who hasn't been in a an actual LEGO set since 2010 (although he and Harry did get figures to be used with LEGO Dimensions), and King Kong, who hasn't ever been featured in a LEGO set.
- Cirque du Soleil: Worlds Away takes elements from the seven Cirqu Du Soleil shows in Las Vegas.
Massive Multiplayer Crossover / Film