List of cameos in Wreck-It Ralph

Focused around video game characters, Wreck-It Ralph features numerous video game characters from multiple publishing companies alongside the film's cast of original characters, much like the 1988 film Who Framed Roger Rabbit.

Disney

 * Tiny the T.Rex from Meet the Robinsons (Appearing as a Generic video game Dinosaur in Game Central Station, heavily resembling Sauron from Primal Rage)
 * Maximus from Tangled
 * Mickey Mouse on a Double U Dee's (WD's) billboard located behind Litwak's Arcade and Family Fun Center.
 * One of the game portals in Game Central Station reads "TRON".

Disney Interactive Studios

 * Sora from Kingdom Hearts (In the Tapper scene, you can see an 8-Bit version of him in his Kingdom Hearts attire at the bottom-left corner of Tapper.)

Nintendo

 * Bowser (King Koopa) from Super Mario Bros.
 * A Super Mushroom from Super Mario Bros.
 * Princess Daisy from Super Mario Bros.
 * Rosalina (Rosetta) from Super Mario Galaxy
 * An NES controller as the vault to Sugar Rush's CPU room.
 * (debatable): various turtle characters resembling Koopa Troopas (depicted here as resembling their in-game sprites rather than their official artwork).

(Note: Mario and Luigi, the protagonists of Super Mario Bros. were intended to have appeared in the film, voiced by Charles Martinet. However, the producers couldn't find a place to work them into the story, that felt right for their significance, along with paying a hefty licensing fee. However, Mario is mentioned by Fix-It Felix in the film.)

Sega

 * Sonic the Hedgehog from Sonic the Hedgehog
 * Miles "Tails" Prower from Sonic the Hedgehog (Picture on a wall in Tapper's Bar.)
 * Dr. Robotnik (Eggman) from Sonic the Hedgehog
 * Amy Rose from Sonic the Hedgehog (on the arcade cabinet of Sonic the fighters alongside some other Sonic characters; her younger self from Sonic CD is used)
 * Knuckles the Echidna from Sonic the Hedgehog (on the arcade cabinet of Sonic the fighters)
 * Bean the Dynamite from Sonic the Hedgehog (on the arcade cabinet of Sonic the fighters)
 * Bark the Polar Bear from Sonic the Hedgehog (on the arcade cabinet of Sonic the fighters)
 * Fang the Sniper from Sonic the Hedgehog (on the arcade cabinet of Sonic the fighters)
 * Neff from Altered Beast
 * Cyril the Zombie from House of the Dead
 * (debatable): AiAi from Super Monkey Ball
 * Saw-Hand Cyborg from Cyborg Justice

Capcom

 * M. Bison (Vega) from Street Fighter II
 * Zangief from Street Fighter II 
 * Chun-Li from Street Fighter II
 * Cammy from Super Street Fighter II
 * Ken from Street Fighter
 * Ryu from Street Fighter
 * Blanka from Street Fighter II
 * Beholder from Eye of the Beholder
 * The car-breaking bonus stage round from Street Fighter II
 * Sheng Long from the Street Fighter series (his name appears as a graffiti at the portal leading to Sugar Rush).

(Note: Dr. Wily from Mega Man was originally set to make an appearance in the Bad-Anon villains support group as shown in an early render image. However he was cut in the final version of the film and replaced with Smoke from Mortal Kombat.)

Midway

 * Kano from Mortal Kombat (aka "Cyborg")
 * Smoke from Mortal Kombat
 * Paperboy from Paperboy
 * Bartender from Tapper

Namco

 * Clyde from Pac-Man
 * Pac-Man from Pac-Man (depicted here as resembling his in-game sprite rather than his official Namco artwork)
 * Inky Ghost Monster from Pac-Man
 * Blinky Ghost Monster from Pac-Man
 * Pinky Ghost Monster from Pac-Man
 * Taizo from Dig Dug
 * A Pooka from Dig Dug
 * A Fygar from Dig Dug

Gottlieb

 * Q*bert from Q*bert
 * Coily from Q*bert
 * Slick from Q*bert
 * Sam from Q*bert
 * Ugg from Q*bert

Konami

 * Frogger from Frogger
 * Yuni from Dance Dance Revolution
 * Leonardo from Teenage Mutant Ninja Turtles (on the arcade cabinet of Teenage Mutant Ninja Turtles during the opening time-lapse shot)
 * An Exclamation mark (!) from Metal Gear

Atari

 * Paddle 1 and Paddle 2 from Pong
 * A racer from RoadBlasters

Taito

 * An Alien Invader from Space Invaders (on a picture)
 * The Qix from Qix

Data East

 * Peter Pepper from BurgerTime

Williams Electronics

 * Knight and Ostrich from Joust

Blizzard North

 * (debatable): Diablo from Diablo (referred as "Satine")

Other

 * Beard Papa the Japanese cream-puff store brand mascot (as the Sugar Rush candy-kart factory security guard, voiced by John DiMaggio)
 * Skrillex as the DJ at the Fix-it Felix Jr. 30th anniversary party.

Mentions and Allusions

 * Mario from Super Mario Bros. (by Felix at the Party)
 * Lara Croft from Tomb Raider (Used by Wreck-it Ralph as a false name when trying to get past Surge Protector.)
 * Aerith from Final Fantasy VII (Refrenced and written in graffiti as Aerith Lives on a subway wall in Game Central Station.)
 * Leeroy Jenkins (Shown as graffiti on the Terminal Wall of "Jenkins")
 * GLaDOS from Portal (Used as a nickname by Vanellope to Ralph referring to "stepping out of his comfort zone. Incorrectly pronnounced as "Gladys.")
 * A caricature of Director Rich Moore (seen behind Ralph in Tapper's).