ARIA has Aria Pokoteng, the "Mars cat" that functions as the president of Aria Company. He's not particularly smart or funny, and can only speak using annoying baby talk. This gets even more obvious in the anime adaptation, where his constant loud interruptions often get in the way of the interactions between the other characters. Still, he gets shoved in almost every scene, and the characters in the story can't help but proclaim how cute and interesting he is.
Beyblade: Daichi in the the third and final season. Basically a exaggerated Copy Cat Sue of Takao with a very irritating voice who gets just as much spotlight, leaving Max, Rei and Kai with less screentime.
Bleach: For the Invading Army arc, the writers created Nozomi. With Rukia's personality and Orihime's Healing Hands, Rukia and Orihime had no role beyond shilling her. Kon's canon modsoul background was rewritten to justify Nozomi's existence, give her Yumichika's unique Energy Absorption ability (but stronger) and make her Kon's Love Interest (reducing Ichigo's role from Main Character to sidekick). Faster than even Ichigo's unique development, she took only 1.5 days to go from powerless to saving Yamamoto's life from enemies too powerful for even him to defeat. The writers also broke their own rules for modsoul death (instantaneous reversion to pill-state) to give her a protracted Heroic Sacrifice everyone could weep over.
The first season initially led some fans to resent Suzaku for his Moral Myopia and nonsensical idealism that constantly got in Lelouch's way, with several believing the creators were somehow trying to favor him. However, this too was subverted in time: Suzaku was Rescued from the Scrappy Heap after a lot of suffering and he eventually came to abandon the more annoying parts of his idealism, which made him tolerable or even likable in the eyes of many detractors.
D.Gray-Man has developed their own Creator's Pet in the form of Johnny. Initially a very minor and forgettable character that would appear among the other members of the Science Department. But clearly through the power of the mangaka's love, Johnny's role in the manga increased tenfold after the arc with Noah's Ark, appearing more in the manga than the second main protagonists Lavi and Lenalee. And while he is supposed to be a normal human, he seems to live through several near death experiences and injuries that are fatal to more minor characters, much to the chagrin to the fanbase. When he isn't nearly dying, he is crying or thinking about Allen Walker (the main protagonist) in a very obsessive way. We're also supposed to assume that Allen and Johnny are close friends, though this friendship was never seen developed on screen even though 80-90% of the manga focuses on Allen's life and experiences in the Order. To find a fan who loves Johnny is extremely rare in the fanbase, most seem to simply wish for him to go away and for Hoshino to remember she has other characters.
Dragon Ball Z gives us Broly. Not so much for his anime appearances (Though he does show in three movies, getting more ridiculous on each of them), where he's more of a Base Breaker. However, he certainly qualifies for his video game roles, where he keeps on getting more and more absurd stuff to do (Bonus Boss on a game that covers waaay before he even makes sense to show up in? Sure! Super Saiyan 3 transformation? Why not! And have him in every game!). Note Americans love him, so he doesn't count on there, but on other places, especially Japan (where mocking him is a meme), he's this.
Broly's creator even openly criticizedBattle of Gods solely for the fact that the character of Beerus, who is well received by the fans, wasn't as "scary" as Broly, and that the movie "reduced Broly to a pushover". Sure, ignore all the other heroes and villains established as clearly stronger, why dontcha? It ain't Watanabe or Toriyama's fault you created Broly too early and didn't capitalize on the whole Dark Saiyajin Messiah / God of Destruction motif that was staring you in the face when you had the chance…
Agon of Eyeshield 21 became this to many fans during the World Cup. To elaborate, Agon's original purpose was to be the heel of the series. While every other antagonist was a lovably quirky Worthy Opponent, Agon was a completely unsympathetic Jerk Jock. Unfortunately, it seemed that Inagaki and Murata found his character to be Affably Evil and was thus promoted to Token Evil Teammate, and the was Character Focus of the arc (sharing the position with Gao). Regardless of whether you hated him, loved him, or loved to hate him, pretty much all fans agree that Agon shouldn't have gotten as much attention as he did (even more then the main character).
InuYasha: The Anime rewrote canon to make Princess Sara the one person who managed to love Sesshoumaru (canon: three people did: Rin, Jaken, Kagura). A pure-hearted girl willingly turns into a demon via Naraku's method (canon: only an evil heart can do this). The demon made stealing Tessaiga look easy (canon: if it was that easy, Sesshoumaru would already have it). Toujikin can't hurt the demon because it's a hate-filled sword (canon: Toukijin's hate is what makes it a powerful youkai-killer). Kagome's sacred arrows make the demon stronger instead of injuring it (canon: impossible, sacred arrows = purification = youkai death). Only Tessaiga could hurt it. Sesshoumaru never met the girl before she became a demon (she was a Stalker with a Crush he once distantly heard the flute of), and spent most of the time dealing with the demon's personal vendetta against him (reason never given). The girl randomly starts fighting the demon control, asking Sesshoumaru to save her which Sesshoumaru (randomly compassionate) does by defying Tessaiga's barrier (canon: he can't do this) to injure the demon and free her soul. In short, creator heaven, canon hell.
Keroro Gunso: Joriri, an anime exclusive character. An annoying, one note joke, poor role model who apparently taught many lessons to the young Keroro and friends. Did we mention he wasn't mentioned until 150 + episodes in? Fans tolerated his presence in the fan favorite flashback episodes...until he appeared in the present, bumming it in the base. That officially graduated him into Creator's Pet territory.
Magical Record Lyrical Nanoha Force is a rather bad case of both the protagonist and the villains being this: on one hand, Thoma is a newcomer to the world of Nanoha, but the Remember the New Guy way with which he is introduced, and the fact that he's instantly liked by pretty much every member of Nanoha's team, certainly reek of author bias.
Much less ambiguous is the case of the Hückebein, the villains of the piece: they are a bunch of Villain Sues with New Powers as the Plot Demands who have been wiping the floor with Nanoha and her friends ever since their introduction, and show no sign of stopping anytime soon. Only the introduction of the AEC Weapons gave the good guys a slight edge, and even so, the Hückebein are still at an overwhelming advantage. They are also very unsympathetic, slaughtering entire villages and communities while claiming they only do it to survive - but the delight they take in killing simply doesn't mesh with the Woobie, Destroyer of Worlds image they're supposed to project. Despite this, the author spends more time focusing on the Hückebein and their escapades than writing about Nanoha and Thoma, and he seems to be genuinely shocked that the readers don't like them.
The Uchiha from Naruto hit this trope running and never looked back. The clan started to dominate the plot around the Sasuke Retrieval Arc and then took full swing in The hunt for Itachi and Sasuke Arc and onwards. The sharingan has a knack for creating abilities just so they wouldn't lose. Also, they're given a genetic Freudian Excuse, that they can cross the Despair Event Horizon after losing someone precious to them. Not to mention pretty much all of them are Karma Houdinis, because all the Uchiha on screen get a peaceful death while another character mourns them and the Uchiha who instigated a rebellion get their crimes permanently swept under a rug like they never happened.
Itachi Uchiha. He was already skirting it just by being an Uchiha. The manga's author is on record saying Itachi is his favorite Akatsuki; unlike other 'powerful' characters, especially the other members of Akatsuki, Itachi has never been humiliated in a fight or ultimately revealed to be incapable of dealing with another character just to hype the latter. Other characters have praised him on more than one occasion, calling him a genius and a hero, and recently he was literally resurrected just so he could have the spotlight one last time. He has all the qualifications, and is considered two thirds of the fandom to be a Scrappy with a very, very Vocal Minority which loves the character shilling he gets. There are three main camps in the fandom. People who think he's awesome, people who hate him, and people who originally didn't really have strong opinions either way until he started getting an unecessary ton of said shilling, from Hashirama praising Itachi as better than him to Hiruzen stating Itachi was as wise as him when he was seven, at which point they got sick of him.
Sasuke Uchiha. He starts off having fangirls in-universe from the outset of the series, and is treated and looked at considerably more highly than the main character despite being an aloof jerkass (although he did get better for a time). His defection causes so much emotional turmoil that neither Naruto nor Sakura could ever truly accept that he'd become an enemy even when he was out to destroy Konoha and everyone in it, instead spending much of Part II working to try to bring him back, even if they have to do it by force. This results in Naruto especially repeatedly sacrificing himself, disobeying orders, taking beatings, begging people Sasuke wronged to forgive him, and furiously hating anyone who bad-mouths Sasuke without a personal stake in his actions. And over the course of his interactions with Itachi during and after his vengeance for murdering their clan, Sasuke goes from wanting to destroy Konoha and everyone in it to wanting to protect Konoha and everyone in it because Itachi's sacrifice would be meaningless, which instead results in his entire descent into darkness and its effects on those closest to him beforehand being handwaved out of mind aside from lingering trust issues on the part of comparatively minor characters. Not to mention that, being one of the Uchiha, he has an annoying tendency to shoot new powers out of his (and somtimes his allies's) ass whenever the plot deems necessary. Even so, his ultimate battle with Naruto still comes to pass following the Fourth Shinobi World War, however with the excuse for it being "Sasuke thinks he'sLelouch now and Naruto intends to smack him back to his senses for good" this has an Easily Forgiven conclusion written all over it.
The Uchiha madness continues with Villain Sue Madara Uchiha. For starters, almost all the damage that Tobi ever did was possible thanks to him. When he is first resurrected, he wipes out the entire fourth division including Naruto, Gaara and Onoki with meteors as well as Rinnegan, Eternal Mangekyou Sharingan and Mokuton. Then, he proceeded to wipe out the five Kages with hardly any effort on his own part, and revealed that he knows how to cancel Edo Tensei release in the meantime even though everyone else got released including Itachi. Much later after Obito is defeated, he hijacks Obito's Rinne Tensei using black Zetsu to resurrect him instead of everyone else. He is even able to extract and seal all the tailed beasts within a few minutes even though it normally took 3 days with a full party member of Akatsuki. No other villain, not even Obito or Sasuke can bend most of the plot to his own will. Kishimoto even tries convince the readers that Madara is a sympathetic character because he is cursed to love too much by the Uchiha genes and that he loves his brother Izuna so much that his death is the reason Madara has become who he is. He's so powerful that the author pretty much had to have the Sage of the Six Paths, who can easily be considered the series most powerful character, come back from the dead and give Naruto and Sasuke a power-up just so that the series doesn't have a Downer Ending. Oh, and after the killer revelations in the end surrounding his entire scheme (see two bullets below), even he still gets a rather peaceful death, spending his last moments being Easily Forgiven by Hashirama and contently accepting his fate.
Pokémon often has a problem in balancing the screen time of the titular creatures.
May's Squirtle in the Battle Frontier arc had elements of this as well. Despite being an untrained baby, it knew moves that it shouldn't, won battles that it shouldn't, and stole screentime away from all of her other Pokemon. And among long-time viewers, it certainly didn't help that Ash used to have a Squirtle of his own, except his wasn't a Marty Stu and had a much more interesting personality.
Paul was also what brought on another Creator's Pet: the Chimchar he previously owned. Due to Ash and Paul being rivals, Chimchar was what really connected the two; Paul being who released Chimchar and Ash taking him in. It was sure to be a major storyline seen throughout Sinnoh, and Chimchar was indeed well-liked at first as people enjoyed watching him grow as a strong member of Ash's team against what Paul wanted him to be originally; even evolving to his final stage, Infernape. The problem is his screentime was too much and he became an eyesore to watch as he went on to continuously beat 2 Pokemon against each of the remaining 4 Gym Leaders and defeating 3 of Paul's 6 Pokemon in their league match. The rest of Ash's Sinnoh team suffered both in characterization opportunities and in battle. The best example of this consequence is Turtwig: After having a good showing in his baseform, he only beat one Gym Leader's Pokemon note Candice's Sneasel as a Grotle and got endlessly curbstomped as a Torterra outside of Team Rocket skirmishes.
Slayers has Pokota, a Bratty Half-Pint trapped in a Ridiculously Cute Critter form and who has an angsty backstory. His personality was said to be based on a character who appeared later on in the Light Novels. This might not have been so bad (though he IS still annoying), but Pokota just so happens to be a Black Mage on par with Lina Inverse and a Magic Knight wielding a replica of the Sword of Light. These two things, plus his bratty behavior and the fact that the plot of Slayers Revolution all but revolves around him definitely makes him a contender for being a Creator's Pet. The worst thing is that while many "guest stars" in the Slayers anime do share similar traits (Filia could be annoying and Xellos has power levels equal to that of a God-Mode Sue), Pokota largely isn't *funny* in a comedy show and yet gets a lot of screen time, a strong sign of a Creator's Pet.
Sonic X: Chris Thorndyke. From the second episode onward, Sonic was reduced to a minor supporting characterwho hardly speaks, while all the attention was on Chris. Characters will only be praised for saving the day if Chris played a part in it, however little (and he'll always be given even praise by the one who did all the work). The way he obsesses over Sonic makes even Amy's attraction look perfectly normal. He also completely usurped Amy's role of Shadow's conscience in the Sonic Adventure 2 adaption, so that he could hog more of the spotlight at the expense of not allowing Amy to show her Hidden Depths.
Berry Shirayuki (a.k.a. Berry Sue) from the Tokyo Mew Mew A La Mode manga. This was not helped by invoking the very rare instances of replacing a shoujo series' star character without giving the series an explicit Retool. Not helped was that the manga was not written by the original creator and gelled so badly with the original that most people relegate it to Fanon Discontinuity.
Yu-Gi-Oh! 5Ds: Crow, commonly hated for being a Canon Sue due to his Common Marty Stu Traits—childhood friend of The Hero and The Rival, Game Breaker deck, a flying D-Wheel, and is adored by the children of the city. His importance to the series and the hatred he got from the fans would only increase as he became the Fifth Signer and got a Blackwing-themed Dragon to go with the position, both events retconning the backstory that is the basis of the entire series. As of the second season Crow was the third-billed hero of the show second only to Yusei and Jack, but his character was nowhere near as explored or developed.
To twist the knife more, he's also a Replacement Scrappy to the former third-billed hero Aki, a Dark MagicalAction Girl with a much deeper character arc and more interesting backstory. Aki was Demoted to Extra once Crow arrived and her character arc became weaker and lost focus as a result. The end credits are almost mocking of this—in a montage of the heroes Yusei, Jack and Crow are listed as their positions on Team 5Ds (Third Wheeler, First Wheeler, Second Wheeler) while Aki is listed as "Benchwarmer". Furthermore, several of the episodes where Aki got to shine again still somehow involved Crow in their plots.
The production crew members' Twitters have shed a bit more light on this: turns out Crow wasn't a Creator's Pet at all! Rather, his deck was a marketing executive's pet. After his first appearance, nobody predicted that the Blackwing cards would sell as well as they did, and when the numbers came in, the card company execs ordered the anime crew to make him a main character. This ended up torpedoing a lot of things the creators intended to do, including a rematch between Rua and Bommer that would've presumably resulted in Rua getting his dragon a season earlier than he actually did as well as a full backstory for Demak, who ended up a Generic Doomsday Villain in the final product. No matter what side of the Crow debate you're on, it wasn't the creators' fault at all; they were probably as annoyed as his haters.
Yu-Gi-Oh! GX: Johan/Jesse Anderson was the first undisputed Creator's Pet (not to mention Marty Stu) of the franchise, stealing the spotlight from Judai's friends and becoming the secondary protagonist during the third season. It was hinted that Johan may have known Judai before, and he was The Chosen One of something, however neither point was elaborated on. Thus in essence, Johan became Judai's best friend in only a few episodes, but there was no real reason given why he was so important. A major part of the season revolved around the protagonists getting sent to an alternate dimension and trying to find a way home. And they did...by having Johan get his ultimate monster Rainbow Dragon. Oh yes, and when he and Judai dueled the Big Bad, Johan performed a Heroic Sacrifice to send him home. From there on the series focused on Judai and his friends getting back to the alternate dimension to save Johan who had been left behind. He would return in the 4th season, where once again teamed up with Judai to duel the main villain again. (Incidentally, this made him unique among the surviving characters introduced in the third season; O'Brien was severely Demoted to Extra and Jim was Put on a Bus despite both of them being far less hated.)
It should be noted that if any other character had dared showing up so suddenly just to be perfect he or she would have been hated instantly. Johan on the other hand is very popular.