Brad who's practically a Disney equivalent of Dash.
The title character fell into this a lot, especially early on. Jake was quick to praise himself - only to fall flat on his face when things got tough. When he shed the ego, he'd be a force to be reckoned with.
Animaniacs: In the episode "Broadcast Nuisance", the Warner siblings provide (admittedly poor) service to Dan Anchorman, host of a news show, who has been shown to be arrogant, rude, demanding, and egotistical. Being rude to the Warner siblings is very bad for your mental health. (The Warner siblings have been shown capable of being polite and apologizing -when treated accordingly.)
Aqua Teen Hunger Force: Master Shake constantly refers to himself in ways that assume whoever he's talking to has heard of him and always believes everything should involve him in some way. He's also a Know-Nothing Know-It-All who's clearly making it up as he goes along, and more clearly thinks he's getting away with it.
Batman: The Animated Series: In the episode "The Clock King", Temple Fugate sincerely thinks that the guy who shares his seat at the subway after one year had to know his name, or that Counselor Hill knows his impending legal case simply because his law firm is handling it, or that he gave the Advice Backfire on purpose. This is also the best way to sum up Riddler's world view in most Batman related media and the animated series is no exception. He claims to be a genius and even smarter than the "World's Greatest Detective" and will go to great lengths to prove it.
Chowder: Mung Daal often thinks that he's the greatest chef around. While his greatness is debatable, he does at least outstrip his rival Endive in actual commitment (Endive values dignity above all else, which leads to methods which seriously abrade Mung "It's not even edible if there's no love" Daal).
Danny Phantom: Appropriately-named Dash Baxter is a slight variation in that only the audience and the main characters see through his self-image, the rest of the characters viewing him exactly as he views himself.
Duckman is another main character who embodies this. Duckman's awareness of how pathetic he is varies from episode to episode (and sometimes from scene to scene). When he's not being this trope he's usually being a Jaded Washout (with little middle ground in between).
The Emperor's New Groove: Kuzco was this at the beginning having absolutely no doubt that everyone admires him. That turned out not so right.
Brian Griffin spent years working on a novel entitled Faster Than The Speed of Love which turned out be a complete rip-off of the Iron Eagle film series, even though Brian claimed he never saw any of them. Everyone who had heard of the book's plot mercilessly taunted Brian about it being a rip-off but he refused to acknowledge it. When the book did get published yet did not sell a single copy after being critically lambasted, the next day Brian read a rave review for a celebrity self-help book and thought self-help books were the reason the novel sold so terribly. He then decided to write a similar book out of spite; the book became popular and Brian slowly began raving "I have created a best selling PHENOMENON" until he was taken down on Real Time with Bill Maher. Brian is also egotistical when it comes to women. Brian always tries to act intelligent and suave to impress women so that he can easily have sex with them, but whenever they break up, Brian tends to blame the women he dates as the reason they broke up instead of admitting that his negative behavior was his own fault. One episode has Brian being confronted by every single woman he ever dated and they all point out how flawed he is, only for Brian to retort with flaws he sees in every woman he dated, saying it's their fault their relationships with him went sour.
Quahog Channel 5 news anchor Tom Tucker, who has earned multiple comparisons to Ron Burgundy (and not only due to his Badass Mustache).
"Do you know who I am? I'm Tom Tucker, dammit! I make more in an hour than you make in two hours!"
Miss Turtle from the episode "Mickey vs. Shelby" thinks she's the best parent in the world, but she gets sucked into her own ego to realize that she treats Shelby poorly. So she blames the person watching him.
Goofy became this when he got replace by Von Drake's automatic waitering system, thinking he can do more than be a waiter without any skills.
Inspector Gadget, far more so than in the film version. This actually is a major element which preserves the status quo. Most notably, he is convinced that Dr. Claw is so terrified of him that MAD packs up and leaves as soon as Gadget is assigned to a case. This may be the main reason he canonically can't catch Dr. Claw, despite the number of times they've been physically close: Gadget cannot believe Dr. Claw would dare go near him, and thus cannot recognize him. To some extent, this is also why Inspector Gadget tends to not notice MAD agents trying to kill him or recognize the MAD logo.
My Life Me: Birch Small especially when it comes to her artworks. She shows off her own "manga art" to her manga idol Miyazaki Lee, which the idol claimed to like only to insult a different "local" comic also made by Birch, which prompts her to bitch him out and start insulting some of the very work of his she was praising earlier.
Rubberdubbers: Finbar the mighty shark who considers himself to be the most fearsome shark in the sea. Ar ar ar
Rocket Power: Otto Rocket. While he's a highly competent athlete with enough skill of a pro skater, he does tend to overestimate himself very often. The episode "Super Mcvarial 900" is a great example of that.
Samurai Jack: we're introduced to Da Sam'rai in one episode: a flamboyant, rude, and aggressive poser who, to his credit, does manage to take down some Mecha-Mooks with Confusion Fu and Fighting Dirty before calling out Jack. Jack demands they fight with bamboo and utterly schools him, so Da Sam'rai draws his sword and gets utterly schooled by Jacks' bamboo again. To the man's credit, though, he does man up enough to shove Jack out of harm's way when Aku's minions show up, and gets acknowledged as having potential to be a real samurai for it:
Jack: You have taken your first step to the true path of the samurai.
Season 5 shows that he ultimately gave up on his samurai career and now runs the Bad-Guy Bar where he and Jack crossed paths. He still loves to brag about the experience and thinks the soul-changing encounter is more impressive than the various injuries and mutilations passing bounty hunters had received from Jack.
The Simpsons: Kent Brockman is an intentional copy of Ted Baxter. In the episode where Marge stars in "A Street Car Named Desire" musical, the director, while competent, sees himself as this supreme director even though the only play he ever mentions directing was a school play. He prides himself on it though, by carrying the review around and quoting it.
"Play enjoyed by all!"
The Smurfs: Brainy Smurf will brag and moralize to his fellow Smurfs in invariably any situation, only for his advice to be dubious at best and completely wrong at worst. (In the animated series, when one of the Smurfs tires of him, he will be thrown out of the village ...) He believes his quotations (compiled in volumes usually titled "Quotations From Brainy Smurf") will get other Smurfs to see him as a great orator and with insightful wisdom, although the quotes are little more than nonsensical ramblings, or copied wisdom from one of his fellow Smurfs. He thinks of himself as a de facto second-in-command whenever Papa Smurf is gone or needs someone to reinforce his authority, but this authority is often better handled by other Smurfs.
Sonic SatAM: Antoine sees himself as a heroic, intelligent "and so very handsome" Freedom Fighter who can take Swatbots in their thousands. In reality he is a sniveling Dirty Coward that often acts as The Load. Sonic and Sally, though much more genuinely competent, frequently have Idiot Ball moments due to their conflicting egos.
Squidward aspires to be an artist, and thinks living next door to idiots like SpongeBob and Patrick while working as a cashier at the Krusty Krab is beneath him. He's not a very good musician, and all his paintings and sculptures seem to be of himself.
Sandy plays with this. She is actually the most intelligent and talented member of Bikini Bottom by far. However this does lead her to overestimate her skills at times and sometimes gets rather overcompetitive and arrogant when someone implies she is isn't the best at something.
South Park: Cartman though he displays a number of tropes at a number of different times. There are also several occasions where Cartman was incognito and openly tried to make his image look better if someone didn't say anything cool about him, even if he had to blow his own cover to do so.
Steven Universe: Peridot. She has referred to herself as "The Great and Lovable Peridot", takes any chance she can get to show of how smart she is, will use her newfound metal powers any chance she gets just to show how great she is, and post-Heel–Face Turn believes herself to be the new leader of the Crystal Gems.
Storm Hawks: Finn whilst a talented sniper, is nowhere near the ladies man he thinks he is.
Sushi Pack: Tako considers himself to be a great artist worthy of the world's admiration, but his abstract paintings are less than admired by anyone, even his own teammates. One episode, in fact, had him chasing down the bad guy not because he stole all the art in the museum, but because he stole all the art in the museum except for Tako's paintings.!
Teen Titans: Control Freak is actually fairly competent as villains go, but the Titans still don’t take him seriously. He wasn't even mentioned on the list of "villains to watch out for" the Titans East got when they were housesitting the tower!
Ezekiel in World Tour is also one of these, thinking he's going all the way even when Gwen reminds him that he was voted out first last time.
Tyler, who thinks he is the greatest athlete around, but constantly proves to be possibly the worst.
Blaineley has a very high opinion about her TV host abilities that seems unwarranted considering the TDWT Aftermath's reveal she was fired from her old show.
Scott in Revenge of the Island is a Smug Snake who thinks he's a Magnificent Bastard. Lampshaded late in the season when he thinks a trap he put up worked (it was actually Zoey's) and he exclaims, "Hey! One of my traps actually worked!"
Transformers Animated: Henry Masterson, aka the Headmaster is very deliberately a parody of this trope. During the season two finale, Starscream builds a small army of clones of himself, each of whom represents an aspect of his personality and almost all of whom are references to the G1 Seekers. The Thundercracker homage, "Egomaniac Starscream", represents...well, it's in his name. Starscream has a pretty high opinion of himself, but at least he can back it up (to everyone except Megatron).
Dr. Venture. He is a slothful and incompetent "scientist" who has ridden his father's coattails his entire life. He often believe he is the life of the party and highly desirable even when no woman wants to have anything to do with him.
Dermott Fictel, Hank Venture's teen-aged friend, seems incapable of opening his mouth without uttering a conveniently unconfirmable boast. He teaches ninjutsu (actually wears padding and takes hits in a self-defense class), can hot wire a car (except Hank had the keys), can fly a plane (except the Ventures' jet is the wrong class for his license), and is also known as "The Wolf" and/or "Psycho" (to the guys in his old neighborhood who supposedly fought a gang war over the choice). He is also a Know-Nothing Know-It-All, claiming that the Retsyn from Certs mints can be used to make napalm, and a Boisterous Weakling, since the only time we see him actually fight he loses to the show's most notorious wimp.