Twins and Junior. Very few actors besides him could have pulled off Junior, although he had a beautiful chemistry with gifted actors Danny DeVito and Emma Thompson.
There's also the Jackie Chan version of Around the World in 80 Days (2004), in which Schwarzenegger plays a self-obsessed sheikh. How self-obsessed? He has a statue of himself displayed on a pedestal in his hallway. When the plucky heroine is running away from his unwanted marriage proposal, she bumps into the pedestal, causing it to tilt dangerously. Arnold's reaction: "No! My statue of me!" The heroine then gets away from him by holding the statue hostage until he agrees to let her go. note By this point, Arnold had already been elected Governor of California.
In this old scene, from a film adaptation of "Duffy's Tavern,"Bing Crosby assembles a group of peers and friends in the industry, all actors/actresses and performers, and they "rehearse" a rendition of "Swinging On A Star" - but with the animal types describing hackneyed actor personas rather than types of people. The joke, of course, being that each of the "hack actor/actress" types they describe are themselves, or roles they're known for playing - including Bing.
The League of Gentlemen movie Apocalypse is a Take That! to the League themselves, displaying them as petty, spiteful and childish. Ironically, the characters from the actual programme become more developed as they realise their behaviour is based solely on the way they're written and not on themselves as people.
Near the end of Scott Pilgrim vs. The World, Comeau is heard in the background saying "No, I saw it, it's just the comic book is better than the movie."
In Steel, Shaq misses a wastebasket basketball shot. Later he's tasked to throw an object into a small opening near the ceiling. His Fourth Wall breaking response? "I never make these!"
A similar gag appears in Scary Movie 4, where he needs to make a basket as part of one of Jigsaw's schemes. Dr. Phil is also in the room with him, and has a self depreciation moment of his own, eventually having an emotional breakdown over not actually being a doctor.
In one of Uwe Boll's better movies, Postal, the German director has an appearance as himself in a theme park he created called "Lil Germany", which is full of Nazi themes. During an interview, he makes jokes at his own expense, such as funding his terrible movies with Nazi gold and being aroused by all of the little children around him. A little later, Vince Desi, the creator of the Postal games, tackles Uwe Boll and attempts to strangle him for what he's done to his games.
Every Mel Brooks movie. Ever. Usually featuring a caricature of a Jew played by Brooks (who is in fact Jewish) himself.
Bullwinkle repeatedly makes these jokes, arguing that the jokes have not become "stale and hackneyed" because they always were, and asking "what's the difference?" when being told that "Really Bad Television" was being renamed "Rocky and Bullwinkle Television."
Indiana Jones and the Last Crusade has a meta example. When Indy confronts Panama Hat and tells him that the Cross of Coronado "belongs in a museum", Panama Hat retorts with: "So do you!" He's saying this to a character in a movie from 1989, who's an obvious throwback to action heroes from the 1930s.
In Roxanne, C.D. is unimpressed by a heckler's insult of "big-nose" and one-ups him by delivering twenty superior insults.
The BBC documentary Knuckle: Bare Fist Fighting shows Irish Travelers using self deprecation to insult each other. Each prospective boxer loudly insists that he's "no good" at boxing... but he'll still beat the tar out of the rival clan's champion.
Argo has Ben Affleck's character being told "You can teach a rhesus monkey to be a director in a day." Affleck admitted to NPR's Terry Gross in an interview on Fresh Air that the line was partly him poking fun at himself.
8 Mile. Alongside the subsequent pretender diss against Papa Doc, this is the main reason for Jimmy's win in the final rap battle. He pre-empts Papa Doc by acknowledging every possible diss he can use against him, but that despite all that he's still fighting on. The crowd admires his honesty, and Papa Doc is left without any material.
This Is the End has Seth Rogen and his Hollywood friends play themselves as a bunch of vain, self-centered idiots. The movie begins with the Rapture, when all virtuous people are pulled into heaven in dramatic beams of light. At James Franco's house party, nobody notices that anything exceptional has happened. And then there's Channing Tatum...
Muppets Most Wanted, in the grand tradition of self-deprecating humor in the Muppets, has a number called "We're Doing A Sequel" with the following lyric:
In The Adventures of Elmo in Grouchland, there is a scene with the Sesame Street gang in jail where Big Bird sings the "Alphabet Song" to a bunch of grouches who are in jail with him. Their response: "Lemme outta here! It's torture! Let us out!"
In R100, about halfway through the film, it will occasionally cut to a small focus group who are also watching the film. They make nothing but critical statements about the film and point out plot holes. When it's time to resume watching the film, they reluctantly stub out their cigarettes and trudge back into the theater.
Guardians of the Galaxy includes points where no-one knows who Star-Lord is (referencing just how unknown a character he is compared to the likes of Thor and Captain America) and one of the characters stating: "This might not be the best idea."
Ant-Man has multiple characters snickering at the name of the character, leading to this line in the trailer.
Scott: One question... Is it too late to change the name?
Quentin Tarantino has a tendency to do Creator Cameos in his films, but usually casts himself as particularly stupid and unpleasant minor characters who die rapidly and unpleasantly.
Much of the humor from The Kid & I comes from Tom Arnold's unrestrained potshots at himself and his career.
In The Addams Family, when Baby Pubert becomes a sweet angelic baby due to an illness, Grandmama explains what might become of the child:
Grandmama: He might become... a lawyer. Gomez: I WON'T LISTEN!
Though it should be noted that Gomez enjoys being a bad lawyer with many failed cases while the implication with Baby Pubert is that he might turn out to become a "proper" lawyer, something absolutely horrifying to the Addams.
Sci-Fi HorrorAnthology FilmGalaxy Of Horrors has some self deprecation built into the wraparound story: The premise is that an astronaut's vessel is breaking down and starts playing the segments of the film as an entertainment program, and he's actively trying to stop the movie (especially because it's taking up fuel that could be used to generate oxygen and let him buy more time to be rescued). At one point he even shouts "I don't want to watch this!" in exasperation.