A question writers should ask themselves when deciding which (if any) Super Powers to give the protagonists is "Which and how strong a set of powers does a character need in order for this story to be entertaining?". The reason why is because many times characters begin or end up having powers that in the hands of a competent and reasonably intelligent protagonist would allow them to handily solve a plot. Plot complications, the Sorting Algorithm of Evil and the Sliding Scale of Villain Threat would be incapable of dealing with this character... at least not without drastically changing the setting or the story's tone.
This is a common problem for sequels of works that end with the protagonist unlocking their full power. Once they get too much power they win the Superpower Lottery and become godlike, or worse, Suelike. On the other hand, a simple or limited power can lead to viewers asking "Why don't they just use his power of X to do Y and stop the bad guy/get the MacGuffin?". In order to challenge the protagonist the writers will have to ramp up the villain's power, find a way to otherwise remove or sideline them, Depower them or at least reduce it to more reasonable levels, take away their weapons, or give them a Drama-Preserving Handicap of some sort. Otherwise, the character will be Too Powerful to Live. The easiest way to tell if this trope is in effect is when the writer resorts to handing the protagonist the Idiot Ball and Forgot About His Powers to keep the character from using their powers in a straightforward way.
On a bit of a tangent, there's a reason why this trope applies mostly to protagonists; we expect the Big Bad to have a nigh unbeatable edge and get beaten nonetheless, giving us a typical underdog story. Though this isn't to say it's good for a villain to have a Story Breaker Power, because they run the risk of becoming a Villain Sue. This is why most stories with such villains actually focus on stopping them from getting these powers.
The abilities most likely to be Story Breaker Powers without careful use are:
Master of Illusion; a person with enough creativity and power over hallucinations and other such trickery could get away with whatever they wanted to, especially if their target doesn't know that they have such powers.
It's worth clarifying that yes, characters with these powers can and often do have engaging stories, great struggles, and otherwise captivate the audience. When that's the case, it generally is because the writer finds a way to properly integrate the power into the story rather than just shoehorning it into a stock plot probably originally intended for non-powered characters; ways to do this can for example involve complications that the hero legitimately can't easily solve by just throwing their power at them, and giving the downsides of having said power some spotlight time as well. In short, whether or not a given power is a "story breaker" depends on the story in question just as much as it does on the power itself.
Compare Deus Exit Machina and Story-Breaker Team-Up, where this trope appears not because of a power itself but because of disparities between them. Game Breaker is a similar but otherwise unrelated trope, when a player manages to inflict this on a game. When instead of personal powers it's a certain kind of Applied Phlebotinum that has this story-breaking ability, see Holding Back the Phlebotinum for ways writers deal with this kind of material.
There's a list of at least a dozen characters, if not more, who are explicitly so broken no one can touch them except maybe a few other people on the broken list. There's a character who can make you fall into a coma if you ever think even the slightest negative or confrontational thing about her anywhere in the universe that's undefendable except with a Power Nullifier or Anti-Magic. There's a guy who's powerset includes the ability to be +1 in power to whoever he's fighting, can hit you with an instantaneous attack from anywhere that ignores everything but causality and destroys whatever it hits, and defends the same way PASSIVELY. Or the guy who can completely negate and make useless anything he thinks of "as a weapon". There's so many of them they actually balance each other out.
Even counting all of the magical human characters, almost note There are at least two human characters who are stronger than God. nobody can really top angels on the power scale, which have the capability to utterly annihilate all life on Earth within minutes, and that's nowhere near their full strength. Fortunately, angels are not particularly hostile: the two times one has been fought, it was being compelled to fight against its will.
Claire Stanfield from Baccano! has a story-breaking Charles Atlas Superpower - despite being ostensibly a normal human, he's strong enough to take on anyone in the series (and a few in other series), including the resident demon/Eldritch Abomination and a vampire. Word of God is that he purposely didn't give Claire his own plotline because there's no one in the series who could possibly challenge him, which generally doesn't make for the most interesting story. He says he is tied for the third strongest character in The Verse, only losing out to an Eldritch Abomination that's a black hole and a character whose defining characteristic is being the strongest man ever.
Letzt Stil vastly inflated Uryuu Ishida's abilities to such a degree he was capable of one-shotting both a captain and his bankai at the same time. It gives him complete dominance over reishi. In a world made entirely out of reishi (Soul Society or Hueco Mundo) it can destroy the world itself to give him limitless power. The author made the ability temporary, burning out the Quincy who uses it, destroying their power forever. Uryuu later regains his power due to Parent Ex Machinaand eventually the story introduces a different variant of this technique called Vollständig, which can be used freely because it doesn't burn out the Quincy's power afterwards.
Aizen's Shikai is complete control over the five senses. Once hypnotised by the Shikai, a person will always be so vulnerable to the illusions they won't even know they're ensnared. Since everyone of note in Soul Society has been hypnotised, it's impossible for them to beat him even when working together. Ichigo only stood a chance because he had not been ensnared and, by the time they fought, Aizen was so drunk on power that he willfully discarded his sword due to the belief he had gained even better Story Breaker Powers than ever.
Yamamoto's Shikai is capable of killing every person for many miles around and he has to erect barriers to protect humans living outside the battlefiend before he'll use it. The only way to combat Yamamoto is to seal his power and then fight him physically. Even then, Yamamoto is so overpowered he can thrash the enemy with his bare fists alone... and if that's not enough, his kidou power is insane as well. His Bankai is The Power of the Sun. Activating it will destroy Soul Society by accident if switched on for too long.
Orihime possesses a Reality Warper power that is an in-universe mystery. Characters have speculated that can do anything if she believes she can and that she's never tapped into her full potential. She is exactly as strong as she believes she is, which is both her greatest strength and her greatest weakness. Her personality is her limitation. She's so gentle, pacifistic, kind and unassuming that she cannot harm others, not even enemies, and it doesn't occur to her that she can break the laws of physics even when told she can.
Ichigo's Final Getsuga Tenshou, easily defeated Aizen when Aizen was at his most powerful. As with Uryuu's Letzt Stil, using this form was temporary and burned out Ichigo's powers quickly. Also like Uryuu, Parent Ex Machina ensures that he eventually does regain his powers.
Barragan's power is Senescencia. He slows down everything around him by manipulating time and aging everything at incredible speed. In resureccion, this upgrades to Respira, a black smoke that rots everything that comes in contact with it and which travels large distances at extreme speed. Speed, Bankai, Kidou are all useless. It's so overpowered that the only way to defeat Barragan is by turning Respira on himself as even he is vulnerable to his own power.
The Key Of The Twilight from .hack//SIGN is rumored for being this within the confines of The World. It is said it allows the user to contradict the rules of the system and basically do whatever the hell they feel like doing. The REAL Key of the Twlight is Aura. She herself can do this (As her daughter later demonstrates) and is more or less the world itself.
Code Geass gives its protagonist Lelouch the Geass, a miraculous mind-control power... that he actually uses a lot less than his favored Batman Gambit and military strategy. To combat this, the show gives him a Restraining Bolt in the fact that the Geass can only be used once on any specific person, though there is no specific limit to how complex, long, and detailed that one instruction is, which means that a pre-planned use of the Geass could allow Lelouch to command the actions of a person's entire life over the course of several hours.
Angemon, and later MagnaAngemon, both seem to be on par with Digimon one level above their own. Patamon first digivolved to Angemon in order to defeat Devimon (the first Big Bad). Much later when all of the Digimon evolved to their highest-level forms in order to face Myotismon (Ultimate for all 7 others), it was Angemon's attack that destroyed Phantomon, one of Myotismon's most powerful subordinates at the Perfect level, and his attack had a debilitating effect on Myotismon himself whereas no-one else could touch him until Angewomon came along. Angemon finally gets to digivolve to Ultimate just before the end of the show, and does the majority of the work in defeating Piedmon, a Mega-level digimon that had already beaten the combined might of WarGreymon and MetalGarurumon twice. This is explained by Angemon, being an angel, being naturally strong against evil Digimon, while being no more powerful than another of his level against anything else. Angemon then spent most of Digimon Adventure 02 getting Worfed.
In Digimon V-Tamer 01, Arkadimon is pretty much the most powerful Digimon period. It can damage a Mega-level digimon at the in-training stage. Not just any Mega, but the above-mentioned Piedmon (to be fair he was already injured but that is a five level difference for a monster that still had five more levels to evolve to!).
The protagonist's very own partner, Zeromaru. As pointed out, it's usually more than just his uncanny strength that gets him by in fights (since many of his opponents are higher leveled) but when he reaches his Mega stage... he unlocks the Ulforce, a Healing Factor so strong that he can recover from instant death attacks! Even Daemon had to negate it before he started whooping ass.
Taiki Kudo and Shoutmon serve as an in-story example in Digimon Xros Wars: The Young Hunters Leaping Through Time. As the legendary general and the Digimon King respectively who saved the world in the preceding Digimon Xros Wars, the Watch Man is understandably concerned that his very presence will destabilise the balance of the Digimon-hunting game. So far, he's being proven very correct - Taiki and Shoutmon have spent most of the series so far effortlessly curbstomping everything that Tagiru and Yuu have trouble handling.
Digimon Xros Wars itself has Shoutmon X7 Superior Mode. He digixrosses with Thousands, if not, millions, of digimon that appeared in the entire digital world, and one shots the big bad with it in one slash. Consequently, it has NEVER appeared again since.
Several characters have the ability to use Solar Flare and Destructo Disc, but they never think to use them together. However, after Frieza, it becomes a moot point because the main villains can all regenerate.
The devil Akkuman emits waves that amplify every evil or impure thought, causing even saintly people to explode from within. He was defeated only because Goku has a totally pure heart and could not be affected. Unsurprisingly, he never appeared again after the story arc featuring him.
As seen in the movies and video games, apparently Goku can absorb the energy of the Spirit Bomb to supplement his own strength. This would certainly be more useful than just throwing it instead (which has worked a grand total of once in the entire series).
Vegito, the fusion of Goku and Vegeta is (discounting the movies and GT, where Gogeta, a fusion of Goku and Vegeta using a different method, gives him a run for his money) the single most powerful being in the universe, capable of defeating Majin Buu's most powerful form with ease, despite not even needing to go beyond Super Saiyan 1. Even after being turned into a piece of candy, he was still too much for Buu. However, after he gets Buu to absorb him (as part of his plan to free those absorbed by Buu before defeating the demon) something about Buu's insides makes Vegito defuse.
The Super Saiyan transformation itself. After defeating Frieza and his immediate family, there are no more naturally occurring individuals in the universe that are powerful enough to even threaten the Super Saiyans. Even the Kais, the Gods of the series are simply not powerful enough. This is why the only serious threats afterwards had to be a biological android which uses their own DNA against them and an Eldritch Abomination created by magic.
Lucy becomes this by the end of the Elfen Lied manga. Her vectors become so strong that she can single-handedly combated an entire army with little apparent effort. Partially subverted in that she was unable to sustain that level of power for long, and ignoring her limitations caused her to turn to mush.
Fist of the North Star has the eponymous Hokuto Shinken. Every move it has is pretty much a fight ender, and it has a technique for everything. Everything. Kenshiro is very rarely ever really challenged, and his fights tend to end after he gets his first hit in. Only a selective few ever give him a real challenge, or even last for more than a couple of chapters once they seriously begin fighting.
Fans often describe Yuki from Haruhi Suzumiya as the strongest character ever made. Although this is probably an exaggeration, she does demonstrate Nigh-Invulnerability, Super Strength, Super Speed, and Reality Warper powers. Her crowning achievement would be hijacking Haruhi's full power to retroactively depower everyone and rewrite the universe to her liking. Her job is only to observe, however, so her overt actions are limited.
In a world where everybody is pretty darn broken, we have Ophis, a dragon who is also known as The Infinite One. She's fully capable of wiping out anybody in this series, and No Selling the strongest weapon of the series. She has a few quirks of her own such as not really being interested in any fighting as long as someone can kick out Great Red from the Dimensional Boundary so she can "attain silence". Then when she joins the protagonists group, she gets hit with the Nerf stick twice; first from Samael the dragon eater, and by using up half of her already reduced powers to create a body suitable for Issei seeing as he died trying to save her.
Great Red, the strongest character of the series bar none, capable of wiping out a gigantic monster who has an instant regeneration power, something that ultimate devils even have a hard time scratching. Issei's combined form with Great Red was specifically stated by the author as a one-time form only. Fortunately, he prefers chilling in the Dimensional Boundary.
Bakusaiga was introduced towards the end of the story just before the Final Battle, and was immediately lampshaded that the Big Bad didn't stand a chance against it, since it's capable of killing anything that merely comes into contact with anything it's cut and it can kill thousands with a single swing. As a result, the Big Bad immediately steals the sword owner's Morality Pet and traps her inside his body for most of the rest of the story. When Sesshoumaru does finally rescue Rin and use the sword, Naraku's body is instantly destroyed, leaving the only threat left to be solved by Kagome making a wish.
Miroku's WindTunnel, what amounts to his own personal black hole in his hand, which he can use to suck any foe into oblivion. As a result, Naraku constantly manages to find a way to stop him from using it, such as the Saimyosho, whose poison spreads to Miroku should he suck them in.
Giorno Giovanna of part 5 gains what is quite possibly not only the most broken power in all of anime and manga, but in all of fiction. In the final battle of the part, his Stand is shot by the Requiem Arrow, and gains the ability to nullify any action an opponent takes even ones he cannot himself see. In addition, if said opponent is actually hit by the Stand, he's doomed to experience death for all eternity. Needless, to say it's fortunate that this only occurred at the very end of the part.
Vanilla Ice's stand can create dimensional voids by eating itself, and whoever is hiding inside it. While inside his void sphere, Vanilla Ice is invulnerable to pretty much any attack, and can disintegrate enemies by merely coming in contact with them!
Notorious B.I.G., a psychic manifestation of a dead man, which takes the form of a blob that relentlessly consumes any matter, and has infinite durability, range and speed. The only reason it failed to wipe out the protagonists was because one of them had an ability almost ideal to counter it (to an extent), and they managed to make excellent use of their surroundings. Even then the heroes never really defeated B.I.G...
Josuke Higashikata's stand Crazy Diamond has extremely powerful matter manipulation ability, and can turn enemies into books, or fuse them to a roadside statue without any trouble! Oh, and it can also heal almost any injury. Somewhat mitigated by the fact that he can't use it on himself.
Part 4 has Yoshikage Kira, who can atomize people with his stand, or can create time loops, in which his enemies keep on dying.
Fugo was Put on a Bus for this very reason. His Stand Purple Haze produced a toxin that destroyed every living organism that came in contact with it. Araki eventually decided to bench him because it became too difficult to design fights with Fugo around. This was reversed in the light novel Purple Haze Feedback though, where Fugo's ability evolved and gained more interesting uses.
Enrico Pucci started out as simply clever and dangerous, whose stand, Whitesnake, was versatile but lacking in a stand-up fight. Then he made it evolve intoC-Moon, which had less flexibility but a lot more power. Then, just as the heroes figured out C-Moon and had him on the ropes, he discarded and drew again. Cue Made in Heaven, whose power over time allowed him rip most of the heroes to shreds and remake the universe.He does, but still falls to the final boy Emporio Alnino.
A non Stand example is the vampire, Cars the Pillar Man leader, who had achieved Complete Immortality via the Red Stone of Aja. His abilities includes an Adaptive Ability cranked Up to Eleven, an immunity to Hamon due to being capable of using it Up to Eleven in power and finally an immunity to sunlight. This made Cars nearly invincible as the plot had established only sunlight and Hamon could kill vampires. The nearly part comes from two facts, one Joseph had to fire him out of the plot via volcano into space, where he eventually stops thinking from the isolation of being unable to do anything and two is the mentioned Stand powers especially Giorno's ability.
Dio Brando's Stand The World can freeze time. The only reason the good guys are able to triumph is because Star Platinum has the same power.
In Katekyo Hitman Reborn! where Time Travel is as easy as getting yourself shot by a bazooka, Byakuran's ability is to sync with all his selves in different Alternate Universes, with at least 8 tetratrillion worlds where he successfully takes over. Later, a potential weakpoint of his was revealed: none of his alternate selves encountered the Vongola Boxes, leaving him unaware of their powers, and killing him in one timeline kills him in all of them.
Jack Rakan is referred to as a "real-life broken video game character" in canon. Through skill alone he tosses around skyscraper-sized swords with ease, copies physics-defying sword techniques with a glance, and destroys pocket dimensions by flexing, explicitly defying the laws of magic with sheerawesomeness.
Thousand Master Nagi is established to somehow be even worse, though the effect is mitigated by his reliance on a cheatsheet to cast spells and his greatest feats taking place off-camera. His "power"? Being invincible.
Fate also has a game-breaking ability: access to the power of the mage who created the Magic World, effectively making him a Reality Warper as long as he remains there.
The Lifemaker, who goes beyond mere Reality Warper to Reality Maker: within the realm of the Magical World, he's practically omnipotent (logical enough, since he created said Magical World). He's vulnerable to "real" mages, from the physical world, but even compared to them he's tremendously strong. Only Nagi "Invincible" Springfield has ever been confirmed to have beaten this guy in combat.
Evangeline AK McDowell, whose implied power level is so high that Fate ran away from her, stating that he would be at a disadvantage fighting against her. And when she loses any fight, most of the time it's suggested that she wanted to lose.
The Hero of Maoyuu Maou Yuusha is this in a nutshell. If he ever got in a fight, any fight, he's guaranteed to win. The only thing that's stopping him is that he's not trying to cause a war, but instead have world peace by working alongside Demon Queen.
Itachi Uchiha. His genjutsu was so powerful he could Mind Control others without making eye contact with them. An exaggerated portion of the anime is spent detailing how the main character learned how to counter this kind of technique, only for it to be revealed that Itachi's version can't be countered the normal way. And that's before he brings out his trump card which just happens to be equipped with a shield that can counter almost any attack, and a sword which can trap the victim in a world of eternal drunken dreams!
Madara Uchiha. His Eternal Mangekyo Sharingan gives him access to the most broken abilities in the series, and this at some point evolved into the Rinnegan, THE most Broken eye power in the series, allowing him to resist a Rasenshuriken. His fire-based jutsu, an element notorious for being ineffective, is the first of its kind to do significant damage to the heroic cast via dropping two meteors on them. He can also use Wood Release, an element that Uchiha shouldn't be able to use (due to stealing the 1st Hokage's DNA). Oh, and let's not forget that he's an immortal zombie with unlimited chakra that will regenerate from any damage done to him. And he hijacked the resurrection jutsu controlling him, meaning no one can control him any more. Then he was truly resurrected in a living body and become the Ten-Tails' jinchuriki.
The Sage of the Six Paths. Not ONLY did he CREATE the techniques that descended to the series's present day, he also saved the world from the original Eldritch Abomination and split the beast in half, creating nine beasts that threatened the world on their own. With his own power, the Sage also created Earth's moon as a prison for the original beast's corpse. On his deathbed.
Tobi, as host of the Ten-Tails, has a working facsimile of Sage's powers, and has shown the ability to negate aforementioned zombie regneration, spam tailed-beast bombs and erect impassable barriers, as well as use a new element that is as malleable as the Kazekage's sand (although in a more fluid and highly cohesive fashion) and is as destructive as the Tsuchikage's Dust Release (basically meaning liquid black holes that violate the Law of Conservation by erasing all matter not protected by natural energy); Naruto's Sage Mode is just about the only thing shown to be capable of hurting him, but his regeneration is on par with Tsunade's.
Kaguya ate the forbidden fruit of the Shinju which gave her godlike powers. She was singlehandedly able to end wars and destroy opposition, so much so that she was worshiped as a goddess.
Kaguya in particular needs to be elaborated on. She has the Byakugan, the Rinnegan, The Eternal Mangekyo Sharingan, the Corpse Bone Pulse bloodline (Including a One-Hit Kill ash bone attack) a chakra shroud that's more powerful, and just as versatile as Naruto's, and above all else, has chakra on that Dwarfs the Ten Tails itself. In fact, The above mentioned Sage of Six Paths says that not only does he have a fraction of her Mother's powers, but he and his Brother, Hamura, were only able to seal her and the Shinju away, not actually kill her. Even more ridiculous, despite all that's been shown upon ressurection, she's still holding back because she's trying to take Naruto and Sasuke's chakra from them. Meaning that, if she wanted to, she could kill Naruto and Sasuke, who are the reincarnations of her Grandsons, at any time. God Damn!
Whitebeard can cause tsunamis with his Earthquake causing devil fruit, in a world consisting almost entirely of small islands. Specifically referred to in-universe as the power that can destroy the world. No wonder he's been in the background so much.
The Logia fruits as a whole have the potential to be this, as one characteristic that almost all of them share is the ability to allow their user to become the element on which they are based, albeit with the element's weaknesses (for example, Crocodile, the user of the Sand Sand fruit, cannot turn into sand if he is wet), thus rendering them virtually immune to physical attacks. Eneru can turn into electricity, and would've just effortlessly steamrolled over everyone in the Skypeia arc if Luffy's powers didn't just happen to make him a living insulator. While Blackbeard's Devil Fruit lacks that ability, it has the ability to cancel all other Devil Fruit powers if it hits the target.
This is deconstructed a bit after the Time Skip. As it turns out the most powerful characters, including many of those who reside in the New World, have access to Ki Attacks that can bypass the Nigh-Invulnerability that Logia fruits grant. One New World-based character even states that Logia users tend to not last long in the New World, since they're so used to their powers being an example of this trope that they tend to find out the hard way that they aren't anymore. True to that, three villainous characters with Logia powers have been introduced since the Time Skip, every one of them taken down with very little effort.
Apart from being a super robot thing with Frickin' Laser Beams, Nigh-Invulnerability and Super Strength, Kuma can use his Devil Fruit power to basically teleport anything anywhere he wants to by 'pushing' whatever he touches. He can defeat absolutely anyone in a single hit by teleporting a fruit user into, say, the ocean or anyone else into an active volcano. He can also "push" things that aren't even physical, like pushing the fatigue out of somebody and into somebody else, and pushed the pain out of Luffy's wounds. Luckily he seems to be a mostly decent fellow, or at least to have no pressing reason to kill the Straw Hat crew, considering he beat them all at once easily. He also was once on the Revolutionary Army's side, and thus willing to help Dragon's son, but now that he's been roboticized, he is now the Straw Hats' enemy.
Sugar, who serves Doflomingo, has the Hobby-Hobby power. She can turn anything she touches into a toy. From great big animals, to people, to giants, there seems little she can't turn into a toy with a single touch of her body, though she has to touch you. A person restraining her won't be affected. And once a toy, she can place a geas on the person to make them loyal to the crew, so the toy cannot fight back no matter how much it wants to. And as for rescuing the cursed people it likely wouldn't happen because once you become a toy all of history forgets you even existed. Friends, family, loved ones, and enemies will no longer remember you or even that there really was a person with your name.
Saitama in One Punch Man can, as the title suggests, beat anything in one punch. ANYTHING. In a world where kaiju make regular appearances. The manga usually parodies this concept, as the main character is a total Invincible Hero who is bored out of his mind because no one is strong enough to make him use even a third of his true strength and whose backstory is disappointingly simple to the point of boring.
During the final climatic battle of the Yellow chapter in Pokémon Special, it turns out that Yellow apparently has the ability to absorb energy directly into her body as to amplify her other ability, Super Empowering. Giovanni states that the attack she and Pika unleashed, "Megavolt", is 10x stronger than a regular Thunderbolt, an attack with the base power of 95. Thankfully, with the constantly rotating cast, she has never really had the chance since to try this again.
Hiko Seijuro XIII of Rurouni Kenshin has been described by the author as a "Joker in the Card Deck", being the God-Mode Sue of the series. The fact that the author realizes this is also the reason why he rarely appears.
Sailor Saturn can end the world simply by bringing her glaive down. She uses her power a grand total of once - to essentially kill everything on Earth in a Batman Gambit to chase away Master Pharaoh 90. The anime dodges it by showing people stopping Saturn from ending the world.
Sailor Pluto controls time itself and is aware of the future. The manga depicts her stopping time a grand total of once at the cost of her life. In the anime she only pretends to die instead of actually dying, though whatever foreknowledge she has, she refuses to divulge and she has a strict code of honor about not interfering with the flow of time. She largely spends the series as a background character except when needed to move the plot, and largely falls out of the series entirely after Sailor Moon S.
The title character explicitly has the power of resurrection and in the present revives everyone on Earth, while her future self reincarnates Sailor Pluto as a human in the present day. In the anime she does not explicitly have resurrection as a power and reviving people after death is nearly impossible (only twice in the series do the main characters recover from death, and largely only because of the way they died in the second instance).
Alastor is the God of Atonement. Manifesting physically is his "I Win" card. In the novels (and movie), he plays this to incinerate the first villain. The anime saves this for the climax of the first season, in which he blows up everything, sends the Big Bads fleeing, and saves the city from an impending overload of energy all by just showing up. He doesn't have to fight at all—he's just that powerful. However it's supposed to kill the Flame Haze that does it (Shana thankfully is capable of surviving it) and the manifestation requires a truly MASSIVE amount of Power of Existence; unless there's an external source nearby, his mere presence in the human world would create a reality-killing distortion.
The Snake of the Festival is the God of Creation, and he seems to have no problems showing off: infinite power, immunity to flame, Prehensile Hair, and a sword that causes anyone who tries blocking it to sustain heavy injuries (Blutsager). Plus the whole "Creator" bit.
Shinigami started Shibusen to have humans fight kishin because he could not. If he had been freed from Death City when Asura was, the main cast would have had nothing to do. As it is, he's kept effectively useless (combat-wise at the very least) within Death City while the students and his beleaguered staff do the dirty work for him. Aside from the one fight when Asura was inside the city, all we get is tantalising hints via flashbacks and his son, of what this grim reaper's capable of.
Deconstructed with Excalibur; it is the most powerful sword in existence, but he is too annoying to be tolerated by anyone.
Tenchi Muyo Ryo-Ohki: Tenchi and Z, who is introduced later, possess powers from something that's even more powerful than the Goddesses that made the universe. Even before the feats of the 3rd OVA, the 2nd not only has Tenchi effortlessly escaping from inside the event horizon of a black hole, he did this not by moving faster than light or teleportation, but by sheer brute force, as he destroyed the black hole in the process.
In YuYu Hakusho Raizen is stated to have once been the most powerful demon in the entire series. His power was so great that the other Two Kings of Demon World could be easily defeated if he was currently in his prime. What is preventing Raizen from using this power? He's starving. Raizen's power comes from eating human flesh and he gave up the practice hundreds of years ago. Notably on his death bed Raizen still has S class demon power on par with Yusuke's current powers who as far as S class demons are concerned is a runt in the litter. Raizen is said by everyone who knew him in his prime as the most powerful demon that had ever lived and that his power was so great that his enemies would "piss their pants" if they saw him in action.
Captain Atom, even in continuities where he's not a step or two away from Doctor Manhattan (who was originally Atom before the story was retooled), has a wide assortment of powers which should theoretically make him as strong as Superman or Martian Manhunter. He's only held back by the fact that sometimes he's not that bright and that if his containment suit is ruptured, he'll die (and presumably take out a lot of property & lives in the ensuing explosion).
Monica Rambeau, the second Captain Mar-Vell is rarely used for this very reason. She has a myriad of superpowers, including (but not limited to) flight, light-speed travel, and the ability to transform into a being of living energy. Naturally, she falls into Flash territory where she needs to be neutralized very quickly just to give the other Avengers something to do.
Doctor Strange. A long term editorial problem concerns just why Strange can't wave his hands and fix everything. Whenever the good doctor gets involved in any significant way in Marvel's other books, serious Nerfage occurs by necessity.
Franklin Richards, son of Reed and Sue Richards of the Fantastic Four. A Reality Warper on a cosmic scale, he has been largely kept as a child for decades specifically because it has been demonstrated that his mature power levels would be so far off the scale that he would become virtually unusable as a character.
Firestorm can restructure molecular bonds. This grants him a wide variety of superpowers that make him an insanely powerful demigod. His primary weaknesses are that his powers are really hard to use even if you're a genius nuclear physicist and that Firestorm is a Fusion Dance of people who don't always like each other. He also has a Weaksauce Weakness of being unable to directly alter organic matter without debilitating side effects.
There's no reason The Flash shouldn't see the villain and have them tied up and in prison before they have a chance to react. Instead he gets treated like a normal person with a few arbitrarily chosen speed based abilities, with one of the most baffling ones being the ability to vibrate through solid objects. Lampshaded a bit in the New 52 where Barry Allen is informed how fast he can process sensory input is the biggest bottleneck to his powers. At one point he gets shot due to over-thinking, and reverts to just processing the super-speed environment on a somewhat instinctual level.
This was explored in Kingdom Come and JLA One Million. In the former he is made of pure speed and is able to see the narrator in Another Dimension, although he can no longer talk with anyone except Superman, because he's too fast (only Superman's supersenses can hear him), and he's so fast he's constantly blurry, even when standing still. In the latter a future Flash is the sole police force on the entire (heavily populated) planet Mercury, and The Spectre mentions that he is forever alone, unseen by most people in the city he guards "though all feel his presence".
Justice Society featured Jakeem Thunder, who had an all-powerful genie who could do anything he asked. The problem was that the genie often took wishes too literally, and so he was hamstrung... but even then, the writers had to come up with constant reasons for why Jakeem either wasn't around, or why he was taken out within seconds (Mordru and other villains would wisely take Jakeem out first). Alan Scott, the original Green Lantern, would also suffer similar fates, being one of the few beings as powerful as Superman on Earth.
The Legion were given a device they called the Miracle Machine by a race of Neglectful Precursors. Its power? Nothing less than turning your thoughts into reality. It's usually relegated to the their trophy room, because power corrupts, and it would be a shame if they saved a few billion lives while getting corrupted... or something. A later author wrote a plot specifically to remove the literal Deus ex Machina from the plot forever (and make Matter Eater Lad useful in the process).
At the end of Final Crisis, Superman managed to create one to reverse the space-time schenanigans from most of the story. It's mentioned as only having a single use (though a later story showed that it's mere existance afterwards was a warp in space-time as well, albiet in a more smaller area), and that it's so complex, Superman will never be able to create another one again due to the fact that it's magnificence erased it's blueprints from his memory.
Minor character Duplicate Boy can duplicate anyone else's superpowers. He's not in the Legion (he's a hero on some other planet), and a bit of a lunkhead besides.
This is why the Martian Manhunter rarely gets used to his full potential, both in the comics and on Justice League. He has each of the various powers of Superman (although with lesser magnitude; "how" much less varies with writers), but also with Shapeshifting, Telepathy, Mind Manipulation, and phasing, amongst other powers. Okay, so he's vulnerable to fire, but he's been shown to get over that. With the above mentioned problems with Superman, they're even worse for J'onn, which might be one reason why they killed him off in Final Crisis. Lampshaded during Blackest Night: When Black Lantern J'onn is fighting Hal and Barry, he picks up the fire station they are in and throws it into another building, saying "I'm as powerful as Superman. Why does everyone forget that?" Indeed, by the end of the issue he's incapacitated them both.
Loki, from The Mighty Thor. He's only a Squishy Wizard by Asgardian standards. note In Asgard, the kids are all as strong as Spider-Man, for comparison. So, in addition to vast magical power (he is only listed as surpassed by Odin and perhaps Karnilla, another Thor character, so his exact magical abilites are unknown in comparison to someone like Dr. Strange or the Scarlet Witch), Loki is also super strong, super durable, experienced in combat, a genius (though this aspect is limited by his Inferiority Superiority Complex, Unfavorite-ness, and need to defeat Thor no matter what), and is so much of Consummate Liar that he has tricked Mephisto (aka the devil), Norman Osborn, Doctor Doom, Odin, and the heroes of Earth several times over. At least some of these traits need nerfing to keep the story alive.
Ambrose Chase had concentration-based Reality Warper powers that allowed him to alter physics at will in a small radius around himself. Barring taking him completely by surprise (like a particular villain did by battling him in a universe that ran on Horror Tropes and using a bullet of Applied Phlebotinum, hence the past tense), he was practically unkillable. It turns out it didn't take; Chase used his power to freeze his own injury and trap himself in a pocket dimension until the others could extract and rescue him.
Morpheus, the title character of The Sandman, is more powerful than most gods and only cosmic level beings like Lucifer are a real threat to him. On the other hand, he is weighed down with the rules and duties of his office, which renders him more impotent than many of his own dream creations. He is only able to use his full power in directly protecting the Dreaming (which does not necessarily mean protecting himself), and only while in the heart of the dreaming. In the end, The Furies — minor mythological creatures from Greek Mythology — kill him because the act of spilling family blood has rendered him a lawful quarry for their wrath. That, and he wanted to be punished for the act.
His name is The Sentry. He may be the Angel of Death (it's implied he was the one who caused the Plagues of Egypt). He was used by Norman Osborn on the Dark Avengers team because he has Story Breaker Power. After an intense, multi-issue battle with the Hand in Japan in New Avengers, Spider-Man points out that the fight would've been over in five seconds had the Sentry been there to help. Severe mental illnesses kept him from doing too much until his death.
The Spectre. The wrath of God personified. Each major DC crossover event includes the obligatory scene explaining just why he can't help out this time... or he just gets mind-controlled by the bad guys. He did actually help out in Crisis on Infinite Earths (where, with a bit of magical assistance, he fought the Big Bad, who had already absorbed the title's Infinite Earths, to a standstill) and in Blackest Night (pity the Big Bad didn't have a soul).
When Thanos acquired The Infinity Gauntlet he gained absolute control over past, present and future, bent reality to his will, could exist in any location and to move any object, could steal and control souls of both living and dead, the most powerful Telepathy in the Universe and gained access to every source of power that ever existed or will exist. There is nothing that can defeat him, neither Marvel's greatest superheroes, Death, Mephisto or all-powerful cosmic gods, including The Eternity, who is the Anthropomorphic Personification of the Universe itself. The main reason Thanos ultimately lost in the end was because the Gauntlet made him too powerful meaning he could not be with his beloved Death since he was so far above her. The Heart of the Universe from Marvel Universe: The End is basically the same thing only on a multiversal scale, him to defeat every single being in the Marvel Universe, culminating in thwarting the second biggest one of them all, The Living Tribunal. After defeating the Living Tribunal however, he realises THE biggest one of them all, The One Above All, is still infinitely more powerful than him, and TOAA has completely out-gambitted Thanos into recreating the entire Multiverse, but with a few flaws removed.
This has been done right at least once, in Watchmen. Dr. Manhattan is a Physical God who wins the Vietnam War practically singlehandely and should easily dissect the problem in the comic and excise it... except The Chessmaster plays not against his powers but his post-empowering uncertainty to get him to leave the planet. He's also hamstrung by his inability to see time like we do- he knows precisely what powers he's going to use, when he's going to use them, what they're going to do. He doesn't choose to use them, he just watches himself using them. He even describes the tachyon interference with his future sight, in the climax, as "freeing", allowing him to truly act for the first time in forty years.
Unless handled carefully, Wonder Woman's lasso's power to force any being to tell the truth will naturally kill any mystery from a story, since deception spoken by any person who faces this power is impossible.
X-Men: Professor Charles Xavier is the most powerful psychic in the world. By rights, any problems the X-Men face should be dealt with at the speed of thought. As a result, most of the major plotlines the team faces start with either a Deus Exit Machina or a lecture on Mind Over Manners. There's also a vast array of anti-telepathy technology that will pop up whenever the plot demands it. At one point, a high-schooler built an anti-telepathy helmet using plans he downloaded off the internet, then beat up Xavier with a baseball bat. It wasn't one of the Professor's finer moments.
Zatanna is one of the most powerful sorcerers in the DC Universe, and thus generally falls victim to some sort of Drama-Preserving Handicap at least once per story. She notoriously has a Weaksauce Weakness that leaves her powerless if she is gagged, which is usually exploited in team-ups just so that she can't solve the problem before the rest of the JLA get out of bed.
Imperfect Metamorphosis has Rin Satsuki, who can negate, absorb, and to a limited extent redirect all but the most powerful magical attacks. Then she was involuntarily transformed into a Blob Monster who gains the powers of anyone she absorbs. Then she absorbs EX-Rumia, who was already a powerful and indestructible Flying Brick and a horrifically deadly Walking Wasteland. When most of Touhou's Superpower Lottery winners (see below) attacked her at the same time they did little more than annoy her, and that was before she absorbed Kaguya and Mokou and gained Complete Immortality. Fortunately she doesn't want to hurt anyone, and has spent most of her time defending herself, running away, or hiding.
The Royal Death Note lets the user bypass the rule that they must know their target's face and full name. The whole plot of Death Note - Light's hunt for L's name - becomes pointless, since Dark can simply write "L" and kill him. Except...
There is also a Life Note, which allows anyone, no matter how they died, to be brought back instantly. The Death Notes are essentially worthless. Except...
There is an Anti Life Note which is immune to the Life Note's powers. (Un)fortunately, the author forgets about this before it has a chance to pay off.
The granddaddy of all of these is the Everything Note, which can do everything. It can be used for resurrection, time travel, superpowers, teleportation and sex. As soon as it is introduced, any pretence at being a Gambit Pile Up story is gone.
On a meta level, the Reset Note grants a metafictional Reset Button to Dark, which lets him Retcon Khaos's rise to power and making his defeat one of the greatest anticlimaxes ever. If he was smarter about using it, the Reset Note would be even stronger than the Everything Note.
Matthew, if he'd use his powers a little more ruthlessly. He can create just about any legendary-class weapon except ones he cannot comprehend. He can do just about anything with swords in his Mage Killer mode. His Aura Rave Spell gets stronger with every use, and can even be used at half cost and half power...with the boost tacked on!
Shira, the first real villain, can freeze anything in his vicinity. The only reason he lost was because...he kinda wanted to.
Nebiros can read your mind based on certain vibrations in the air, and thus use his Barrier Warrior powers to dismantle your attack, dismantle you, and still have time to evilly gloat.
Dolph Gradich, one of the later villains, is basically Matthew 2.0, making swords out of Majitek Nanites, and having an arsenal of spells at his disposal, as well as Matthew's Aura Rave spell.
In With Strings Attached, Ringo is able to mentally see anything he's ever seen before, and can work his way into unfamiliar places from a familiar starting point, including people and unique objects. And he can do it effortlessly and indefinitely. And he can see perfectly in the dark. And he can see things as small as atoms. And he never holds the Idiot Ball. The concept of “information is power” really applies with him. He's also telekinetic, with an enormous range. Thus, unless you magically hide yourself from him, he will fuck you up—and the plot along with you. As Jeft discovered to his sorrow.
The Oogakari, a family of OC God Mode Sues that jump into canon and mess with the plot and help the main characters sort of behind the scenes, but they are far more interested in seeing how messed up things will be once the new plot unfurls than actually bringing peace to the world. The supposed leader of the family, Ghost, is a walking Class Z apocalypse via his time space burning fire, which gives him the power of "denial of phenomena". In layman's terms, he can negate anyone, anything, any EVENT, any CAUSALITY, any MEMORY, any WORLD, any GOD, or any DIMENSION he wishes by burning the time space that makes them up. This includes the events that possess anytime he dies or gets hurt as well. He is confirmed to be the absolute end of his multiverse and can enact it anytime he wants, but doesn't because "he isn't that big of an asshole".
His Sister, Shadow, is right up there as she contains the supposed Goddess (Demon Dragon Goddess... Thing) Zuzushi, that created their multiverse. As a result she has obtained the ability to "create all from nothing". It's been stated but not shown that she is easily capable of manifesting universes on a whim, and even contemplated destroying and recreating the Narutoverse the current story was in after Ghost trapped her in it while a major event occurred in another universe.
Films — Animated
Aladdin has the Genie, who with phenomenal cosmic powers can do anything aside from killing someone, reanimating the dead, or forcing someone to fall in love. After he’s freed in the first movie his powers are demoted to 'semi-phenomenal, nearly cosmic' for the sequels and Aladdin: The Series, and gets to hold the idiot ball frequently.
Bolt, which is about a dog who thinks he's a superhero when in fact he's simply an actor. One of his powers in his show is a superpowerful bark that can destroy... like 100 mooks, helicopters and cars all at once. Though it's only useful in large open spaces without innocent bystanders.
Zelda from the second sequel to The Swan Princess has the power to create Seekers - homing fireballs that can find any target anywhere and never stop seeking them. The only way to stop one is to break the caster's wand. Of course Zelda's plan is gain the Forbidden Arts and the power to destroy - she remembers at the eleventh hour about her Seekers and sends one after Odette. It works.
In the DVD Commentary for the extended version, Peter Jackson points out and jokes about it that Gandalf could not use the magic he used to turn away the forces of Mordor a second time because he used up all the power in his staff "And all the shops in Minas Trith were sold out of batteries".
At the end of the trilogy Gandalf is able to rescue the hobbits from Mount Doom by using his magic to command giant eagles. If he had done that at the start of the first film then they could have flown straight to their destination and saved a lot of effort for everyone involved.
The Matrix sequels have this problem with Neo, as at the end of the first film he is essentially a god of The Matrix, with the power to do anything he damn well pleases while inside it, the only limits being his own imagination and the ultimate parameters of the simulation. Because of this the writers had to considerably tone down his powers from Reloaded onwards (going from a Reality Warper to a Flying Brick), and up the villain threat. Of course at the end of the first film, the writers didn't know if the movie would be popular enough for a sequel, so this is Hand Waved in the sequel as the Agents got an upgrade.
In Return to Oz, the Ruby Slippers become a literal story breaker once the Nome King is defeated and Dorothy recovers them. Everything is repaired, and the story pretty much ends.
As noted above under "Comic Books," Xavier's power is such that most of the movies would be over very, very quickly if he did not frequently get incapacitated or rendered powerless in some way.
In X-Men: Days of Future Past, Quicksilver gets Put on a Bus after the Pentagon raid because, as that raid shows, he is downright unstoppable. While moving at Super Speed, simply tapping a person is the practical equivalent of getting hit by a heavyweight boxer, and he can take out an entire room of armed guards so quickly that their bullets weren't even able to reach the people they had shot at when he started.
Just possessing the Platinum Flute puts an Adept on par with Mach. In the hands of a master musician (like Stile or Clef), it can invoke magic powerful enough to destroy the planet.
In The Dark Tower, one of the side characters in the last book has the power to materialize anything, including inter-dimensional portals, out of thin air when he draws them on a paper. Guess what happens when he draws something/someone already there, and then erases it.
The Archive from The Dresden Files is a magical construct that places all recorded human knowledge into a single person. Originally, it was created to mitigate tragedies like the burning of ancient libraries. In the modern age, it means a little girl nicknamed Ivy automatically knows and understands everything people write (bank records, nuclear physics, psychology, emails, tomes of necromancy...) without even trying. She's not the only nigh-omniscient character in the stories, but unlike the others, she has full free will and her understanding comes automatically. She understands science well enough to build her own nukes, she knows enough blackmail material to keep most world leaders in her pocket, her expertise with magic makes her a one girl army even compared to the protagonist, and she would become fully aware of any plan against her the moment someone made the mistake of communicating it in written form. What keeps her from making all the heroes irrelevant? She's sworn to neutrality and any steps she took to actually use her power for her own goals would turn every other supernatural nation against her at once, and even her power isn't enough to hold off the wizards, two courts of the fae, the fallen angels, and three nations of vampires all at once. Plus, she's more interested in kitties and otters.
From Circle of Magic, Trisana Chandler's weather magic is treated as one in-universe, hence why Ladyhammer magically breaks nearly every bone in her body. Whether or not it actually is a story breaker is up for debate: it is extremely powerful and can end any physical threat in seconds, but this is a universe where binding even a powerful mage is very possible with the right preparation.
The Tamuli has mind reading. When a member of the race known as the Shining Ones joins the party (who have this power, among many others), she's able to easily see who The Mole is in the party, and find out that he's basically the Big Bad of both the Tamuli series and secretly the Big Bad behind everything that happened in the Elenium series as well. Though by this time, the villain's plans have progressed so far that it STILL takes a book and a half to set things right.
When Sparhawk gets control over the Bhelliom, it offers its own suite of ridiculous powers - worldwide teleportation, the ability to pull information from people's minds from a lot further away than Xanetia can, and at one point it intercedes with the spirit of the world to massively accelerate tectonic activity in one area for a few minutes, causing earthquakes across half the continent. It has other powers that are not used in the narrative proper, such as the ability to instantly kill on contact. Unlike Xanetia, however, this has limitations; its mind-reading in most cases is limited to a general consensus rather than Xanetia's individual and specific scan, preventing it from locating the bad guys instantly, and the villains can detect Bhelliom in action and are holding hostages that they will hurt or kill if Sparhawk takes the Blue Rose out of its box and starts turning people into frogs or something.
Voldemort believes the Elder Wand to be this - and to be fair, it's one of the three Deathly Hallows, making it the Wizarding equivalent of the Holy Grail or the Spear of Destiny (though he's ignorant of this history, having been raised a Muggle). In practice, however, the Elder Wand is a Doom Magnet: those who wield the Elder Wand tend to end up murdered for it, and in the end, it dooms Voldemort himself when he fails to realize that Harry is its true master. When it finally passes into Harry's hands, he chooses to break its curse by never wielding it - and in the movie he seals the decision by snapping it in two.
Time-Turners allow you to travel to the past and create a Stable Time Loop, establishing the way it had always been, basically retconning your own story as you see fit. This means that you can never be ambushed or caught off-guard for you will be/have been warned in advance by your future self. Any important event can be witnessed retroactively, so truth can always be established, even when there were no reliable witnesses "the first time". Naturally, these awesome devices were used once to resolve a minor conflict and then forgotten about only to be casually destroyed later, when ignoring them was no longer plausible.
Galbatorix from the Inheritance Cycle is constantly referred to as impossible to defeat. Not only does he have over a hundred years of experience over Eragon, as well as hundreds of Eldunari and another Rider at his disposal; his voice is said to be his greatest weapon. Up until he discovers the name of the Ancient Language, that is.
Jack Blank's power is his ability to control and talk to machines. The series primary antagonists, the Rüstov, are living machines. One of them is living inside Jack. Normally this means instant death, but Jack's powers keep The Corruption resulting from the infection in remission involuntarily. In the third installment, End Of Infinity, the Rüstov are Genre Savvy enough to saddle Jack with a Drama-Preserving Handicap to prevent him from using his technopath powers against them directly, as well as to speed along the development of his corruption. Once Jack manages to overcome it, he single-handedly destroys the entire Rüstov race with a wave of his hand by forcibly ripping each one out of their hosts without harming the host bodies, then crushing them with a thought.
The Kingkiller Chronicle has the true language. A Nested Story depicts a hero known as Taborlin the Great, who knew the true name of everything and could command it accordingly; after being trapped in a tower, he told the stone to break, allowing him to command the wind to carry him to the ground. A couple only intermittently-properly-pronounced names stuttered out without fluency (the name of the wind) almost qualify in themselves, and when a character accidentally pulls off a full phrase the words instantly turn a fairy queen, one of the most powerful beings in the world and a literal sexual predator whose entire nature revolves around trapping and never releasing men, into a simpering soft-hearted love-slave that lets him free when he 'bluffs' her with a painfully transparent 'trick'.
Larry Niven once wrote of this problem, which he encountered when he introduced the General Products Hull. The hull couldn't be damaged by anything except gravity or antimatter. Introducing this into the universe could potentially ruin a lot of stories and he ended up setting most of the stories before the hull was invented.
Teela Brown's "luck gene" prevented anything bad from happening to her unless it led to an even better outcome. Niven wrote one last story set after all humans were supremely lucky, then mostly gave up on setting any stories later.
In the Liavek books, if you ask Elmutt a question, the answer he subconsciously prefers will come true. This doesn't seem impressive, until you get to questions like "What will become of me?" or "What could possibly go wrong?" He doesn't seem to be able to change the past, but he can radically alter people's physical conditions, kill people, more or less brainwash them, and on one occasion doomed a man to be killed by a particular person. Once the first story is over — when Elmutt knows how his powers work and has sorted out his issues — it's more or less impossible for a story involving him to have dramatic tension, unless the question is asked by someone who has no idea what they're really doing. He's only had two total appearances in the series — his origin, and an unnamed but plot-relevant cameo two books later.
Necroscope's Harry Koegh his virtually unlimited teleportation power, and makes the climaxes of his stories anticlimactic, especially combined with the near omniscience his ability to talk to the dead grants. Basically he knows all about you if you've killed people, and can drop a bomb on your head no matter how heavy your defenses.
Lila Black in Quantum Gravity eventually becomes consumed entirely by her mechanical half and becomes a story breaker as a result. Book four reveals her to be capable of forming just about anything metal, as well as having limited control over metal and machines, and nigh invulnerability; her body reconstructs itself after being smashed to pieces, and doesn't even need to breath. And that's aside from the Armour, a fey, which can transform any way it likes and tends to trick attacks into backfiring, or the shape-shifting weapon of intent that warps reality in response to what she wants. On her return to Demonia she battles through an unspecified number of opponents without the slightest scratch, or even needing to devote much thought to it. The loss of the weapon tones her down in book five, and by the end of the series she is looking less overpowered by deed of simply encountering an even more dangerous opponent.
In an obscure children's book called Samantha Stone and the Mermaid's Quest, Samantha spends much of the book trying to learn how to teleport - both herself and objects. She gradually becomes realistically better at it, able to teleport herself and others, but often not exactly where she intends. But by the end, Samantha is teleporting behind enemies to knock them out, teleporting out of ropes when tied up, and teleporting captured prisoners out of a cell. The villain only undoes this power by binding and gagging her, thus preventing her from casting the spell. However, the story ends shortly after that, on a cliffhanger.
The Star Wars Expanded Universe has had a lot of writers in it over the years. Many of them gave Jedi in general and Luke Skywalker in particular New Powers as the Plot Demands. Sometimes it's used well, sometimes it's not. The Black Fleet Crisis out of nowhere gave him an unexplained control over rock - he effortlessly collects the ruins of a shattered castle and assembles it in the air, then makes those heavy dark stones change to a different kind of stone and flow and make a new castle, which forms and closes openings that can be used as doors and windows whenever he wants. No other books have given him anything like this power, and it's never been used again, although the ability to basically waterbend stone could certainly have come in handy.
Timothy Zahn, who wrote the first modern EU books and had heroes and villains who relied more on guile than force (or Force), complained about the tendency of writers to make Jedi incredibly powerful, as he considers that boring. On a hilarious side-note, Zahn's main villain (Grand Admiral Thrawn) somehow managed to turn Art Appreciation into a storybreaker power, because he was just that much of a Magnificent Bastard.
Noah Watanabe's every-growing power does break Brian Herbert's Timeweb trilogy, since he has no Kryptonite Factor and no qualms about interfering for the greater good. However, Herbert deserves a certain amount of credit for keeping him under control for two books without using the Idiot Ball.
Nina Theroux can control people's will simply by looking at them in the eye. The show sometimes makes up excuses as to why she can't just "push" the bad guys left and right (since theoretically it would make the job too easy and a drama television show can't have that). A good example of this is in "Anger Management"; when Nina was questioned why she couldn't "just push [the] kid", she revealed that her power only lasted for a couple of minutes and "Rosen doesn't like to work that way". Well, that's too bad because it would have resolved the conflict MUCH sooner and easier.
We're extremely lucky that Jason Miller, the all-powerful hormonal hive-mind gathering alpha, is just a lonely teen who just wants friends and has no psychotic motives.
Misty Day is a gifted witch whose main power is her ability to resurrect the dead by touching them. She can do this to anything dead, from birds, to alligators, to people, to herself after she was burned at the stake. Moreover, she can heal serious damage inflicted upon the corpses of those she revives - she undoes completely burnt off skin and partial bodily decay with contemptuous ease. Misty has resurrected not only herself but two other members of the main cast, and it's gotten to the point where the characters just come to her when someone dies, lampshading it as they go. In order to balance this, two characters have taken to destroying the bodies of their victims in order to keep them from being revived.
Possibly why Madison was killed off in episode three - her telekinesis and fire-starting powers would make short work of the zombie army attacking their house, and would stunt Zoe's arc about her necromancy powers.
Illyria started out as very much one of these. That list of powers likely to be story-breakers? She was pretty much all of the above. She specifically dismisses the Big Bads of the entire series as being like insects compared to her, and not without justification claimed she was a god to the gods. She was so powerful than one wonders why she even needed an army back in ancient times, save that one recalls there were others like her running around. The heroes didn't (and couldn't) beat her; Illyria failed to conquer the world simply because she lost interest. In short, Illyria put the "cosmic" in Cosmic Horror Story. Until she lost control of her powers due to the puny human body she was reincarnated into, and got a Power Limiter slapped on her, taking away some of her powers entirely and dialing the rest of them down so she wasn't much stronger than the other protagonists.
Earlier in season one, Angel manages to acquire the Gem of Amarra, a mystical ring described as the equivalent to the Holy Grail for vampires, from Spike in a Crossover episode from Buffy the Vampire Slayer. This artifact would grant the vampire wearer increased abilities and complete invulnerability to all their usual weaknesses, as demonstrated by Marcus earlier when he shrugs off a bow-to-the-heart from Oz and the ability to walk in direct sunlight without erupting in flames. At the end of the episode Angel, who had remained doubtful about keeping the ring or not, decided to destroy it, preventing the show and Angel's fights from being a lot less suspenseful.
In the fifth season of Babylon 5, although Lyta can mind-control several dozens of people at the same time, there is one person she can not control: Sheridan, who was also Touched by Vorlons.
Samantha from Bewitched and Jeannie from I Dream of Jeannie. Their powers were pretty much "do anything by wiggling your nose/bobbing your head". If it weren't for the random nature of their powers and otherworldly relatives, Darren and Major Tony would lead completely idyllic and boring lives.
The Doctor is the Trope Namer for the Timey-Wimey Ball because without it, he could simply time travel anywhere and change anything, and if he made a mistake just go back again and fix it. This problem was parodied in the Comic Relief parody "Doctor Who and the Curse of Fatal Death," which put the Doctor and the Master in a series of time traveling counter-moves to each other.
The Doctor could just evacuate everyone on the doomed space ship that's getting sucked into the sun, sucked into a black hole, crashed into meteors a la the Titanic, etc, in the TARDIS, if it didn't always (in)conveniently get blasted away into space and out of useful range for the episode.
The Doctor is a member of one of the most advanced races that the universe ever has or ever will produce. If he seriously applied himself to any single project, he could probably end up running everything. However, his short attention span keeps him constantly moving and prevents him from hatching many long-term plans. His seventh incarnation was an unusual exception in that he apparently had a number of elaborate schemes going on. But he rarely bothers to clean up after them.
So many stories would be a lot shorter if the Doctor remembered he can read minds - any of the Whodunnit stories, any stories where someone turns out to be backstabbing the Doctor...
In the first season, Peter Petrelli can permanently gain anyone's power simply by being near them. It doesn't take long for him to rack up flying, time control, teleportation, and healing. With all of his powers, he should be able to achieve just about any conceivable goal. To keep him as a viable character, he's given amnesia in season 2, loses his powers briefly, and then regains them at a significant downgrade.
Hiro's time control and teleportation abilities alone make it necessary for his character to constantly grasp the Idiot Ball so that he doesn't just solve everything instantly.
Kamen Rider Kuuga's Ultimate Form, which despite being a potentially Deadly Upgrade, is also debatably one of the most powerful Kamen Riders. To wit, one of his previous Finishing Moves, the Rising Mighty Kick, causes a 3 kilometer-diameter explosion; the Ultimate Kick has the potential to destroy the planet. In order to keep from overpowering the plot, Ultimate Form only appears in the last two episodes and is mostly used to battle the Big Bad, who is said to be just as powerful and both share a few common abilities like pyrokinesis.
In the theme song to Mystery Science Theater 3000, it's said that Joel could have built a device that could have skipped movies directly to the end. Instead, he used those parts to build his robot friends.
Ascended beings are basically gods, able to command the forces of nature at will to terrifying effect. To prevent this trope, the writers introduced the idea that the Ancients also have a self-imposed Alien Non-Interference Clause. Which, naturally, they didn't apply to the Ancients' Evil Counterparts the Ori when they needed new villains for the Post Script Season.
The Asgard are one of, if not the most advanced race in the entire story (arguably surpassing even the Ancients at least in certain areas) by the end of their lifespan, and also happen to be very kind and helpful protectors of the milky way. So how come the Milky Way is overrun by the evil Goa'uld anyway? The Asgard are at a long-spanning war against the Replicators, a far more dangerous enemy and they're not winning. Add that they are literally a dying race. The only time the writers allowed them to be Big Damn Heroes is in a parallel universe.
Counselor Troi can sense the emotions of most beings. This would end a lot of episodes really quickly if the writers didn't keep coming up with circumstances where her powers are blocked or confused or she's unable to warn the other characters. Some episodes Hand Wave or completely ignore her powers and the impact they would logically have on the plot. In early episodes, she's able to communicate with non-Betazoids (or at least her lovers) telepathically, even across long distances. It's not hard to guess why the writers quietly dropped this aspect of her character.
There's the issue of the entire Betazoid race, and other friendly telepathic species, would seemingly be able to solve all sorts of problems by reading minds. It's a wonder anybody in the galaxy can carry out a hidden agenda. This was demonstrated in one episode where Troi's mother casually revealed that two alien diplomats were really assassins the second she encountered them.
If it weren't for Villain Decay, The Borg would be in here easily. Before Star Trek: Voyager, they could basically copy and negate the technology of any species they came across, and design nanites that integrated the physiology of any species they encountered into their collective. One of their ships could bring the Alpha Quadrant and any races less powerful than Organians or Douwds to their knees. Indeed the Borg were so powerful that no good reason was ever given why the Borg hadn't conquered the entire galaxy: the writers could only combat this by handing the Borg multiple Idiot Ballsand eventually sticking them in many of Voyager's Idiot Plots.
A fifth season episode introduced Jesse Turner, the purported Anti Christ who (due to being a half-demon Half-Human Hybrid) gained really high-level Reality Warper powers following Lucifer's presence on Earth, and was obviously more powerful than any other character seen up to that point. Having probably realized this, the writers quickly abandoned the character by writing him out at the end of his first appearance.
Castiel. Angels are among the most powerful beings in the setting, even "grunt" angels like Castiel effortlessly dispatching most demons and monsters, heal fatal wounds, and even resurrect the dead. While this was fine for Story Arcs where he was fighting other angels who were equally powerful or even stronger than he was, it trivialized the Monster of the Week episodes as Cas could just locate the monster and zap it in two seconds. Thus, the writers were forced to continuously include excuses and storylines which explained why he couldn't help the Badass Normals. In the seventh and eight seasons, the writers continuously toy with the idea of killing or permanently incapacitating Castiel, but they won't because he's one of the most popular parts of the show, and his episodes get the best ratings. Also, he's funny and arguably the show's heart, so his other attributes make the show more enjoyable. The writers just need to figure out how to depower him. Indeed the season eight finale ends with Castiel's grace being taken from him, effectively turning him human.
Ezekiel is worse than Cas ever was. Introduced immediately after the above event, he quickly becomes the show's go-to fix it guy. In nearly every episode since his introduction he has served as some form of Deus ex Machina, including bringing Cas and Charlie back to life, healing Sam from the trial sickness and a slashed neck, and scaring Abbadon away when she and her mooks have the upper-hand against the Winchesters. They try to avert it by saying he's been weakened by his fall from Heaven and doesn't have enough power to be constantly doing this, and yet every time he's needed he's able to muster the strength without issue. But the worst part is, since he's using Sam as a vessel they can't even not have him around when it's inconvenient to the plot like they did with Cas.
Word of God admits that in hindsight they made angels too powerful and have had to come up with numerous Drama Preserving Handicaps to keep them from solving everything single-handedly, hence the proliferation of angel-killing blades and the angels' tendency to Forget About Their Powers. In season 7 they introduced the Leviathans, who were supposedly even stronger than angels, and unlike the angels were all villainous, but a direct comparison of the Leviathan's abilities versus the angels' was still hilariously one-sided in the angels' favor. Season 9 had to issue a species-wide Nerf by casting the angels out of Heaven and burning off their wings, removing their ability to teleport and weakening their other powers.
The Colt, a supernaturally powered gun that can supposedly One-Hit Kill anything. Originally it was limited by the number of bullets it had - any old regular bullet wouldn't work, they had to be enchanted like the gun - so the heroes had to save them for kills that really mattered. In season 3, however, the heroes figured out a way to make new bullets for the gun after extinguishing the original supply. Without the limited ammo, the gun quickly became story-breaking as Sam and Dean no longer needed to figure out monsters' weaknesses and could just kill anything they came across by shooting it. Once they realized this, the writers had Sam and Dean lose the Colt, and replaced it with Ruby's knife, which is also a One-Hit Kill, but only works on demons. The Colt briefly resurfaced in season 5, only for it to be revealed that it actually can't kill everything, as the Winchesters discover to their horror that Archangels like Lucifer are immune. It's lost again after only a single episode in the heroes' possession and never seen again.
The Angel Blade, the primary weapon angels carry which later fall into human hands. Like the original wielder, it is extremely overpowered in that it can kill basically everything in the attic and the basement, including Angels and Seraphs, Nephilim, Hellhounds, Demons, the aforementioned near-omnipotentAnti Christ, and even Reapers. These weapons tend to drop in and out of the story though, and one tends to wonder why nobody tried to use such weapons on the Monster of the Week as they more than likely would work.
Parodied in That Mitchell and Webb Look, where Angel Summoner and the BMX Bandit form a mismatched duo. Angel Summoner can summon angels, which can accomplish essentially anything; BMX Bandit has... BMX skills, making him feel like a permanent third wheel. On one mission Angel Summoner allows BMX Bandit to fight alone, while secretly summoning invisible angels to help him.
The Makuta species has 42 base powers, a strengthened version of the elemental power of shadow, highly dangerous mask powers, and Teridax even possessed secret knowledge about the workings of the universe, allowing him to manipulate matter at will. Plus, they're Energy Beings with no biological needs who can possess machines or soulless living bodies, their personal bodies can shapeshift, and they each have access to a personal Pocket Dimension to store excess mass. And they can absorb other beings to gain mass or simply kill them. How did the writer keep them from demolishing the heroes under a second? Teridax's masterplan required them to be alive, some Makuta were given drama preserving handicaps, they had a constant grip on the Villain Ball which clouded their judgment, and the gaseous substance they're made out could easily be burnt away.
The Skakdi race has access to elemental powers (but only when working as a team, which they hate), each has a unique but highly powerful special ability (like Adaptive Ability, bringing objects to life, conjuring tailor made prisons, Power Copying, etc), and eye-based or mental powers. And one of them called Zaktan is a Worm That Walks who can fly, shapeshift, and become an insect swarm. Fans cried foul when six of them easily beat the Toa Nuva (the most powerful heroes of their universe), so at the end of the story, they got devolved into weaker sea serpents by Mutagenic Goo.
Time Travel is one power that the writer deliberately avoided, citing this trope as a reason. However, he practically abused dimension-hopping. Thus, to tone it down, Brutaka's Mask of Dimensional Gates was destroyed and the only other MODG in existence fused to Vezon, an incompetent lunatic who could hardly control it.
The Golden-Skinned Being has almost unlimited control over matter and is able to make almost anything disappear into thin air. It has powerful telepathy, can easily brainwash others, and through sheer will, create entire new worlds reflecting the desires of others, where these others can be locked away for eternity, out of this universe. The story got Left Hanging after he appeared, so it's unknown how the writer would have handled him.
The Energized Protodermis Entity, an Eldritch Abomination who basically unwittingly set the entire BIONICLE story into motion, can destroy or transform anything with a slight touch. It's also a liquid, so pretty hard to avoid if you're in a room with it. However, it doesn't have control over whether the things it touches cease existing or get transformed. The being itself very rarely appears, its substance acting mostly as Phlebotinum. It's only known weakness is gravity — it flows down big holes.
One of the things that contributed to Dick Tracy 1960s Dork Age was the introduction of the "Space Coupe" and all its accompanying crime tracking and weaponry. Once you give the heroes a device that can go anywhere and track any kind of crime, the villains don't really have a chance. This led to the plot "Villains Try To Steal The Space Coupe" repeated ad nauseum for a while.
What makes a given power a "story breaker" or not in a tabletop RPG context is often the involved group's (especially the GM's) ability and willingness to cope with it in their personal game...or lack thereof, of course. Player character power issues can also be aggravated by the not uncommon tacit assumption that the "PC halo" comes with a fair degree of Hero Insurance, cushioning the characters against what might otherwise be logical consequences of using their powers. For example, the effectiveness of the "scry-and-die" tactic above relies a lot on any prospective targets of potential teleporting assassins imitating Orcus and rarely if ever actually getting proactive about patching that hole in their security.
The joy of being a DM is that you have your own story-breaker power in the form of being able to change things before they resolve; it's fairly easy to roleplay a boss that's far better at Gambit Roulette than the actual DM playing him. A boss monster that thinks ahead when the DM also thought ahead puts up scrying protections to prevent the teleport trick — a boss that thinks ahead when the DM did not think ahead just had a permanent illusion of a throne room put in over a pit of poisoned spikes after the last group of adventurers tried the same thing. And a DM that didn't think ahead and feels that the players were CHEATING on them (perhaps because the players somehow obtained spells they weren't supposed to be able to afford at their level) will point out that since the players didn't see through the illusion (which they cannot do through a scrying spell), the fall surprises them, meaning they cannot roll a save to avoid hitting the spikes.
One Miraculous Arc in Chuubo's Marvelous Wish-Granting Engine is dedicated to having these and festooning them with limitations so that the story can survive. It's known as Reality Syndrome. Generally, they are limited by a) time constraints on how often you can use them, and b) a diagram giving the HG progressively more elaborate opportunities to mess things up as the wish strays further from the character's core truths.
The rulebooks for The Dresden Files make suggestions on this front in two ways. In the section on building opposition, most of the guidelines are along the lines of taking your villain and giving them powers equal in cost to the Player Party's. It suggests you create a group of antagonists instead, since as the party gets more powerful, the villain's powers would make them damn near impossible to fight effectively if the model was followednote One character having powers equal to three or four low-level characters is doable; one character having powers equal in cost to three or four high-level characters results in someone with huge magic potential, is impossible to hit, damn near impossible to harm even if you do hit'em, and will heal fast even if you somehow manage to harm them.. It also suggests that Harry Dresden himself might be one, and gives suggestions for taking him out of the picture. Needless to say, Harry's margin comments are less than enthused about it.
Harry: Billy, this whole section DISTURBS me. I'm making this face at you. Like, the one in the picture right here◊.
Repeatedly casting the "Love's Pain" spell (someone the target loves takes damage, cannot be stopped) on a Mook who you have given Fake Memories of loving your enemy...
The Wish spell, which is pretty much as it sounds. The player wishes for anything to happen and reality will reshape itself to make it come true. There are some limitations, and some downsides. The spell is difficult to obtain and cast, and drains the life force of the caster (read: XP loss) to empower the events. If the wish is something too insane, the caster may die without yielding enough power to make it happen. Second, and usually even more importantly, you should be very careful what you wish for. Just wishing for a lot of gold, for example, may result in all the gold in every king's treasury teleported to you. However, how you will explain that to their armies that are sure to follow is not in the scope of the spell. In fact, the GM is specifically instructed by Gygax on what wishes to give them a chance, in Second Edition, and if the players ask for more, to make SURE they regret it.
Miracle, the divine flavor of Wish, is even more broken: The spell-replicating function of Miracle carries no XP burn and can duplicate the effects of ANY 7th level spell or lower and ANY 8th level Domain spell or lower. Only the massively broken reality-warping function of the spell incurs a possible XP burn. Also, Miracle is not a spell cast so much as a supplication made of a deity, removing the possibility of the spellcaster receiving any magical backlash — of course, if the deity in question (which is to say, the DM) doesn't feel like granting the request, Miracle may simply fail, or end up worse.
Miracle is particularly potent when used by an Ur-Priest, a 3.5 prestige class whose schtick is stealing magic from gods and priests. The god's choices are no longer relevant; since the fluff is that the character is stealing the power from the deity in the first place, the deity no longer needs to approve or disapprove; the caster simply uses the stolen power in whatever manner she chooses. And this would entail no greater or lesser retribution than stealing any other 9th level spell, so if an Ur-Priest is casting 9ths, they've been dealing with that for a while.
Craft Contingent Spell (cast a spell in advance, it triggers when a condition is met) and Celerity (take an extra action, even in the middle of another character's turnnote Which can disrupt that character's turn, e.g. by moving out of range just before they attack.) can be brokenly powerful even when used separately, but Contingent Celerity makes the user impossible to catch by surprise. Throw Time Stop into the mix and well...
Warp is extremely powerful in GURPS, so much so that it is explicitly banned for players in the Dungeon Fantasy books. The authors did eventually cave and add it in with the requirement that the player take a small Unusual Background named "Ha-ha! I Can Teleport!" and isn't able to improve it.
A lot of the drama in Nobilis comes from how everyone and their dog has these and is not shy about throwing them around. That said, due to a particular quirk of reality caused by it being written in a language of flowers, anyone, noble or otherwise, can add some changes of their own, and because this kind of reality tampering is, so to say, rewriting the rules rather than playing along with them, nobles could well see their own powers and domain yanked right from them without any say in the matter. Thus, the DM is outright told none of the players should be granted any related power. Third edition adds a wrinkle where you can do anything, but pushing your power too far - say, using power over snakes to create an Aaron's Serpent, who are snake-shaped gods - causes Actuals to come out of the substrate of reality and start absorbing things, and a few days later you end up with a ship eating Chicago or something similarly difficult to repair.
The Primarchs and the God Emperor are obscenely powerful even for the setting (the first action of Leman Russ after birth was to climb out of a volcano, and later in life all of them casually crushed Greater Daemons), and if they were still around it would devastate the Status Quo Is God so beloved by the writers. Hence they have all, in one way or another, been out of action for ten thousand years, with the Emperor immobilised (possibly dead) and directing the Astronomicon, and the Primarchs either dead, incapacitated, lost, or in the case of the surviving Traitor Primarchs simply content to sit in the Eye of Terror. There is a very good reasons for this, as the one time a Primarch (Angron) decided to do something, he conquered approximately seventy sectors before the Imperium could direct a large enough force against him.
The C'tan had as much power in the material realm as Greater Daemons do in the warp (i.e. Reality Warper levels), fed on stars, and commanded vast armies of Necrons which they created in the first place. They caused so many problems with their mere presence that 5th Edition retconned them into having been shattered into piecesby the Necrons millions of years ago, and the C'tan that had been encountered were nothing but fairly mindless, much weaker fragments of the originals.
The Tyranids can strip a whole planet of biomass, oceans and atmosphere included, in a matter of months, are effectively limitless (the number of creatures in a swarm is reliant on how much biomass they've consumed, and they've already eaten several galaxies), their Hive Mind projects a shadow in the warp that disrupts psykers and daemons within dozens of light years of it, and most critically they have noEnemy Civil War, unlike every other major threat in the setting. Like the Borg mentioned above there has been no good reason given as to why they haven't already already eaten everything in the galaxy and been on their merry way.
In the second game of the Ace Attorney series, Phoenix Wright acquires the "Magatama" which is an special charm that allows its user not only to see if a person is lying after being asked a question but also shows how willingly is that person to fight so their secret remains hidden in the form of many locks, every lock representing a safe measure that the person thought in order to keep their secret, and to top it all, once all of one's Locks are broken, that person will finally admit to the truth and will reveal their secret in full. The power of the Magatama will destroy your soul if you fail at breaking the locks too many times, and its function as a lie detector is limited; in 2-4 Engarde denied killing the victim, and was right to the extent that he didn't kill Juan himself, but hired the man who did.
Gilgamesh of Fate/stay night, as the oldest heroic spirit and original owner of most of history's most famous weapons, has a stockpile of tens of thousands of Noble Phantasms, included among them one of the few swords in existence able to out-power Saber's. Theoretically, he could win almost any fight in seconds simply by virtue of the fact that he has weapons suitable for exploiting the weak points of basically anything he encounters. He is, however, held back by his galaxy-sized ego preventing him from ever fighting seriously, thinking his foes to be 'unworthy' of his true strength. Gilgamesh is so powerful that he´s considered the 4th strongest thing in the Nasuverse (only surpassed by Primate Murder, Arcuied/Crimson Moon Brunestud and the Physical God ORT of Mercury, a 40 meters tall crystal spider with no concept of death), and can destroy entire planets with Ea.
The title character of Mega Man Battle Network. Due to his nature, it is implied that if he were to have access to his full potential, he'd be the most powerful entity on the planet. Demonstrated very clearly in the fifth game where he briefly ascends to this level and destroys the final boss (the manifestation of humanity's evil) with a wave of his hand.
X has unlimited potential. The attempted reboot of his series, Mega Man: Maverick Hunter X, has Dr. Light state that X can evolve as he fights, explaining how he retains certain powers and upgrades between games. The only reason he has problems in battle is his kindness causes him to hold back.
In Super Robot Wars W, the Game Breaker Valzacard is a mecha built with technology far beyond the whole universe, a Reality Warper, has survived the end of the world, and can play with space-time easily. Conventionally, it can erase its opponent from existence and its weakest attack has enough power to obliterate several of the Database Battleships (built with similar technology), making it the most powerful Original Generation in the franchise. The only canonical reason it doesn't beat everything without even trying is because some components are broken and there's no time for repairs, causing its output to be far lower than what it should be.
Tabuu's Off Wave in Super Smash Bros. Brawl has the power to revert all the characters back into trophies, which allowed it to completely curb stomp nearly the entire cast in seconds, with only a Chekhov's Gun allowing one to get free and revive the others. After that, they were only saved from another Off Wave by a Deus ex MachinaBig Damn Heroes moment from Sonic, which depowered the Off Wave enough to only be a One-Hit Kill that covers the entire screen and can only be avoided through rolling and air dodging.
Keine Kamishirasawa has the ability to both remove elements of history and, in her hakutaku form, create brand new history. The actual strength of this ability is unclear, as attempting to "eat the history" of the human village and hide it still didn't prevent the protagonists from detecting it.
The ability to manipulate boundaries is a terrifying ability capable of fundamentally undermining reality. As far as we know, everything is built upon the existence of boundaries. If there was no water surface, there could be no lake. If there was no sky line, neither mountain nor sky could exist. Were it not for the Great Barrier, even Gensokyo itself wouldn't exist. If there were no boundaries, everything would probably exist as a single enormous object. Thus, the ability to manipulate boundaries is by logic an ability of creation and destruction. It essentially creates a new being, or rejects the existence of a being. [...] It's said that this ability is not limited to physical space, but also applies to pictures, others' dreams, and even stories.
Yuyuko Saigyouji has the power to kill with a thought (aside from the two above-mentioned unkillable characters), can control dead spirits, and is smart enough to see through even Yukari's schemes at a glance. She's immune to exorcism as long as she's bound to the Saigyou Ayakashi, and unsealing her would release one of the the only evil creatures in the setting. However, she spends most of her time running her portion of the Netherworld, and rarely takes things seriously when she does get involved in the plot.
Shiki kills things in one hit. Period. No matter what, if you have a concept of death, he can kill you. The limiter factor he has during the story is A. no one tells him what he needs to know, B. he thinks killing is wrong, C. initially he can't fight properly unless put in Nanaya mode, D. overuse will implode his mind since a human mind can not continously perceive death. Also he has a nasty scar that likes bleeding and making him pass out. All of these (except for D) are essentially dealt with by the end of the story, so the sequels so far have given him opponents that he can'tsimply kill, even if he could beat them. Len doesn't want to. Wallachia exists as a unique repeating phenomenon. Arcueid is incapable of dying at night time (usually), and ORT doesn't have a Gaian concept of death because it comes from Mercury.
The direct sequel handles things a little more interestingly. Due to story reasons, Shiki outright forgets his ability, and every time he ends up using it the world melts down, sending him back to the first day of the time loop he's in. When he finally remembers his ability though, he instantly kills the Big Bad of the story with little to no fanfare after a grueling battle detailing how there was no way Shiki could defeat the Big Bad normally.
A full powered Arcueid is one of the most powerful beings in all of the Nasuverse. In terms of brute force, perhaps only the "Types" themselves and people like the dimension-hopping wizard Zelretch and Ado Edem with his reality-cutting sword Slash Emperor are more powerful. Even with 70% of her power suppressed, she has super strength, speed, accelerated healing, ability to exist as a spirit and create a new body for herself if needed, and Marble Phantasm - which via a combination of reality warping & causality manipulation can recreate any kind of natural phenomena. She can even drop the Moon on her enemies, and in her Archetype Earth form she has no concept of death.
A more broken variant is the original Ryougi Shiki's version of this power, where she can "kill" pretty much anything - magic, emotions, ghosts, living people, etc. - and her powers work through projectiles, which just screams for a sniper rifle.
One character in Casey and Andy is Satan. And she has Reality Warper powers. The author has remarked that it's hard to come up with reasons why she isn't using them to help her boyfriend out of whatever jam he finds himself in.
Grace's shapeshifting powers in El Goonish Shive, with her Omega form being the most powerful to the point that she was able to effortlessly defeat Damien, the Big Bad of the Painted Black arc and the most powerful character in the comic at the time. Fortunately, she's usually a pacifist who prefers not to fight unless she has to, and many fights either find a way to take her out of it or put her in a situation where she can't fight at full power.
The timing of Tavros's death comes suspiciously soon after the revelation that his animal affinity extends to First Guardians, and immediately after he asks about using it to get god-dog Becquerel to help directly.
The trolls themselves- being parodies of Mary Sues- nearly all have wondrous, impressive powers that are rare even for their species. Unfortunately, their personalities are so dysfunctional and the Gambit Pileup they get stuck in is so massively huge (spanning dozens of characters, at least two apocalypses, and time travel in both directions) that any attempt they make to fix the situation either fails completely or only ends up making things worse. A recurring theme throughout Hivebent is that if the trolls could actually get past their various issues and work together as a team, they could be heroes.
Jade Harley gets several of these in a row. First, she imprints her dead dream-self into her sprite, creating a version of Jade with godlike power... who is too depressed to use it. Then, she fuses with Jadesprite as part of going god-tier, giving her godlike power and the will to use it... but then the plot proceeds in such a way that she spends three years with her boundless teleport mojo not working for her. Finally, upon arriving in the alpha session, she is hit with mind control by a major villain, caught in a difficult confrontation with a fully-powered Page, knocked unconscious by a surprise hit and finally crushed under a building.
Richard from Looking for Group is a nigh-invulnerable dark mage with vast, vast powers: half the time he is sidelined in one way or another to let the other characters achieve something, the other half he is jarringly abrupt in his resolving of fights/problems. An entertaining character, but problematic.
Vaarsuvius becomes ridiculously powerful through a Deal with the Devil. The resulting arrogance results in a serious backfire/subversion later on when Xykon turns out to be much too well prepared for a simple brute force attack to work. The above-described Scry and Die tactic is explicitly mentioned.
According to Rich Burlew, even with Vaarsuvius having the two most useful spell schools on his banned list, it is very hard to write scenarios that he can't trivialize with the other six spell schools.
He's also stated that he considers true resurrection (the most powerful resurrection spell) a story-breaker, and it will never show up in the comic. He also mentioned that the few monsters capable of casting it naturally would demand at least one life in exchange, which in most cases is too high a price for the characters to reasonably pay.
This is why Petey only rarely gets screen time on Schlock Mercenary. His personal power level is at least an order of magnitude above any of the civilizations in the story, and he is fighting a war against the Andromeda galaxy.
Phantaminum from Tower of God. As an Exis, he is a being that cannot be interfered with. That's all he needs, but he is also unGodly powerful in conventional ways. Fortunately, he is a background character.
Played for Laughs in one Liar Town USA post, describing a fictional TV show called Futuresight: "A wildly successful clairvoyant gambler is persuaded to solve crimes by the FBI. Since he's psychic, he solves hundreds each day. It's no big deal. Then a crime syndicate decides to target him. But they end up in jail, because he can see the future. After that, it's back to gambling."
In Red vs. Blue Wyoming's Time Distortion Unit powers are nebulously defined anyway, but we know at the very least it can be used to loop small segments of time (used specifically by Wyoming to "replay" a situation in which he loses) and slow/stop time around the user. Yet in the prequel bits, Wyoming never once makes use of it, even after we know he has an AI. This is because time manipulation should make it impossible for Wyoming to ever lose—and he very specifically has to at a few points.
Tennyo of the Whateley Universe is so powerful that in her battle at Christmas she ripped a hole in space and time and destroyed an unkillable thirty-foot regenerating monster. Plus, she may be the strongest regenerator on the planet. Her problem is that her powers are potentially too destructive — her "death blow" is Exactly What It Says on the Tin, she can end up irradiating the area she's fighting in without meaning to or noticing, and sometimes when she loses her temper badly enough something seems to get loose that drives normal humans insane with fright before she's even really done anything to them. In "Ayla and the Great Shoulder Angel Conspiracy", the authors figured out how to use her backstory to give her a Heroic BSOD and totally take her out of the game.
Contessa has the ability to see and carry out a guaranteed path to victory. And unlike other forms of prescience in the setting, her power cannot be countered by other precogs. Or as she puts it, "I win."
Bloodbending, which enables the user to control people's bodies, would be this if it were not only usable under a full moon. The only way Katara is able to defeat Hama while she is Bloodbending Aang and Sokka is to use Bloodbending herself. That said, it is shown that Bloodbending multiple people is difficult, and it's doubtful doing it to a large room was within the capabilities of either woman.
Bloodbending came back as a true storybreaker in The Legend of Korra, because it was the only way to create an opponent that would be remotely dangerous to Aang in his prime. With all four elements at his command and the Avatar state under his control, his opponent Yakone had to be a Bloodbending crime lord who could Bloodbend dozens of people in the middle of the day with his mind, and it was still rather one-sided in Aang's favor. Likewise, his sons needed the same ability if Korra, having already mastered three out of four elements, was to be believably challenged.
The Avatar State itself is this. The Avatar is already one of the strongest benders around in each of the four elements. The Avatar State takes that power and increases it to incalculable levels. Aang's ability to enter the state would've been devastating in the original series... if he could use it at will. Of if Korra could have used it at all. At the end of Season two of The Legend of KorraRaava, the Spirit of Light was destroyed and re-bonded with Korra, completely resetting it.
Tigerhawk, the last Maximal to premiere in the show. In addition to being a Flying Brick, he can create giant tornados and earthquakes that lays waste to the Predacons' lair that the Maximals have been hammering away at for three seasons; he can even stand toe-to-toe against Megatron's final form in a one-to-one match, something that not even Optimus Primal in his final form can do. If he was in the Final Battle, it wouldn't last five minutes, which was probably a reason why Tigerhawk died protecting the Maximal base just before the final showdown.
Ben is the wielder of the Omnitrix, an alien device that can potentially turn him into more than one million aliens, several of them with their own set of super-powers. This would, in theory, allow him to handle any possible situation as long as he choses the right form. So of course, this power is balanced by most alien forms being locked, Ben's tendencies to go for the Indy Ploy and the Omnitrix constantly giving him the wrong alien or turning him back to normal at the wrong time. There is a master code that allows to transform at will into any alien with no time limit, but it's extremely hard to unlock and Ben hasn't figured it out. Ben 10,000 has unlocked it and, in the original series' future, ended up becoming so effective he basically reduced police and other heroes to obsolete.
In Ben 10: Omniverse, Ben often has to suffer from Forgot About His Powers so he doesn't win every single fight easily. This includes being too inattentive to check if he's actually picking the right alien, not to mention not using the ones with obvious Breaker powers like the Gravity Master.
Ma-ti from Captain Planet and the Planeteers. Yes, that Ma-ti. While his powers are limited, just like the other Planeteers, he is still the most powerful of the group. He cannot mind control extremely evil people, calm animals that are too scared, read unconscious people, etc. But if Ma-Ti was flawed enough not to resist Zarm's evil charms and he picked up Heart of Conquest in the episode "The Conqueror", he would be able to mind control the world. An Alternate Universe Ma-Ti abused his powers to force sympathy and get rich people to donate money to him freely.
A recurring reason most plots have Rufus and Amberley save The Dreamstone whenever it is stolen, since both the Dream Maker and the Wut army have near limited amount of power that disposes of the Urpneys' plans with complete ease whenever they are finally forced to take action (most exceptions seem to involve them simply standing there hopeless until the Noops do something). This however stills leaves the conundrum of why they constantly decide to send two powerless children into harm's way when they could easily do the job themselves.
Generator Rex has Breach, an E.V.O. with the ability to create portals that go anywhere, including at least one Pocket Dimension where she placed an entire city to be her "dollhouse". The only thing keeping her from completely breaking the story for either the heroes or the villains is that she's too mentally broken to reach her full potential.
The Flash, period. Like the comics, the writers had to find a way to nerf his powers to better maintain tension in the story. When the writers finally have him go all out, Flash completely curbstompsBrainthor. In another episode, the completely unfettered Lex, given control of Flash's body, showed just how deadly the Flash could be if he didn't hold himself back.
Amazo, returned with godlike powers (defeating the defenses of Oa and the entire Justice League at once without really breaking a sweat) and wanting to find his purpose in the universe. He quickly disappears for the remainder of the series after discovering his powers were making a magic-fueled enemy stronger. The writers must have realised that having a virtual god on the good guys' side who can shift planets to other dimensions on a whim and whose superpowers were as beyond Superman as Superman is beyond a normal human, would make the Justice League pointless.
Kim Possible: The title character's battle suit was meant to be a one-shot Eleventh Hour Superpower in the Grand Finale; its enhanced strength, speed and other nifty abilities allowing her to put a definitive beatdown on arch foe Shego, and then ride off into the sunset... er... prom. Then the show was Un-Cancelled and the writers had to deal with a weapon that would let Kim curb stomp her entire rogues gallery. Solution: Split time between making excuses to not put on the suit and having bad guys try and steal it. Up until the other Grand Finale, where Warhok is strong enough to take Kim out, suit or not. Of course then Ron's Story Breaker Power kicks fully in...
The Elements of Harmony are explicitly stated to be the most powerful magic in Equestria, and have swiftly defeated every villain they've been used against. Thus the conflict revolves around actually getting to them, and then making sure they work properly (as they effectively weaponise The Power of Friendship). In the Season 4 premiere the Mane Six sacrifice the elements by returning the items to its source, the Tree of Harmony, rendering them no longer usable.
Discord is a Reality Warper so powerful he's almost omnipotent. The Elements of Harmony are the only thing that threaten him, as he's so far beyond the power of everyone else, including fellow heavy hitters like Celestia and Luna, that it's almost funny. As of "Keep Calm and Flutter On" Fluttershy has made him value his friendship with her too much to risk angering her by returning to his villainous ways.
The series 4 finale villain, Lord Tirek, begins incredibly weak after being imprisoned in Tartarus, but he can drain the magic of unicorns to gain power. After powering up sufficiently, he gains the power to drain Pegasi of flight. And drain Earth Ponies of their strength. Eventually, he managed to drain nearly every pony in Equestria, becoming the single most powerful being in the entire setting... and then he drains DISCORD.
The three princesses transfer their power to Twilight, so by the time she fights him, she is also a Story Breaker Power and able to fight him on equal footing. (It's Deconstructed in Twilight's case, as having that much power in her makes her unable to do mundane tasks without accidently blowing up something.) In the end he pulls a Hostage for MacGuffin to gain the upper hand and the Mane 6 have to discover a new Story Breaker Power to defeat him.
The Sword of Omens from ThunderCats kept getting new powers so it could be the solution to so many plots as the series wore on that it became this. Even when it was destroyed, they just reforged it again.
This is also why the Dark Star Saber goes unused and unmentioned throughout most of season 3. Megatron was already dramatically more powerful than everyone else, with the exception of Predaking and the upgraded Optimus who he winds up using the blade against in the finale.
Even before that, the Star Saber was immediately broken after its' debut episode, since it gave the Autobots an advantage Megatron was terrified of. It gets repaired in the season finale, but it vanishes from the plot until the finale, and even then it's not wielded properly by a Prime, but it nevertheless is used by Bumblebee to kill Megatron. It briefly appears in the Grand Finale movie, but it's never used again, not even against Unicron.
The Shard Of Lightning - which stops time entirely - gives Jack the ability to not only curbstomp the heroes within seconds, but totally humiliate them at any given time, steal the Shen Gong Wu whenever he wants, and basically defeat any opponent without needing any help whatsoever. As he would have become totally undefeatable if he had held onto it, he manages to lose in the end and it's locked away in the vault where no one can abuse its power. This is basically how the show gets rid of every game breaker Shen Gong Wu: lock it away for the benefit of the world, just in case it somehow ends up in the wrong hands.
The Reversing Mirror, mostly due to its having a miriad of uses and little downsides. It can reflect attacks magical or otherwise, it can cause attacks to have the opposite effect, it can override the effects of near any Shen Gong Wu just by being in the vicinity, it can change things that have nothing to do with Shen Gong Wu to their opposite, and can be used in conjunction with Shen Gong Wu most famously by bringing a ghost to life. Pretty much every time it's used by someone with a bit of cunning, the results are extreme: more usage in the series might have brought about some very interesting techniques, but it also would have likely resulted in its user(s) being basically impossible to attack. So it was only brought out when the plot called for it specifically.
The Zeta Project introduces a remote that can control any mechanical device, even Zeta. Eventually, Roe gets her hands on one, but by the end of the episode it is forgotten. And for good reason; if the heroes have one they never have to fight again and if the villains have one they don't need to work to stop the heroes. Ironically, a later episode implied the device was a mass-produced children's toy.