Winds of Destiny Change

""Einstein would turn over in his grave. Not only does God play dice, the dice are loaded.""

- Chairman Sheng-ji Yang, Sid Meiers Alpha Centauri, "Looking God in the Eye"

Essentially, Screw Destiny as a superpower.

A character is able to alter the laws of probability for a local area, resulting in "good luck" for them or "bad luck" for the opponent in the form of random and unlikely incidents happening spontaneously. The Dragon chasing you over a suspension bridge? Use this power, and the bridge's otherwise imperceptible design flaws will suddenly make themselves present, causing the bridge to collapse just as you make it across, but before your pursuer does. Need to stop a supercomputer from launching nuclear winter? This power will cause its software to crash spectacularly.

The only thing bad about it? Usually, you won't have any control over how probability is altered. You can have a specific outcome in mind, but there will always be a chance it won't work, or worse, turn against you at the worst possible time (namely, whenever you're about to save the day). Meaning your control over the forces of reality... well, y'know... isn't. This may mean that while the universe will look out for them on the big stuff (their survival, saving the world) they might be very unlucky in normal life.

This is for characters who can actively and consciously change the laws of probability in their area, or if such alterations would constitute a Necro Non Sequitur. Just having everything go your way is being Born Lucky. Keep that in mind when adding examples below.

In games, this kind of ability may be represented by a Luck Manipulation Mechanic.

Because almost everything theoretically has a chance of happening, when cranked high enough this power begins to overlap with Reality Warping. When this power lacks punch on the other hand, it can easily slide into What Kind of Lame Power Is Heart, Anyway?. Sometimes it even alternates between the two and sometimes it can be both. Immune to Fate is related to this trope in a sense, but not completely comparable.

Has nothing to do with They Changed It, Now It Sucks. Although that would make for a good laconic description. That might be a bit too meta, however.

Anime and Manga

 * Orihime from Bleach possesses the power to reject fate (dressed up initially as more typical Magical Girl-type abilities). This ability eventually draws the eye of the main antagonist.
 * As of recent events, it's been revealed that the Hogyoku also possesses this ability, albeit to a bit less of an extreme than Orihime.
 * Judai of Yu-Gi-Oh GX, though he's apparently much better at screwing destiny against a Knight Templar possessed by a Cosmic Horror than fighting fate against a demonic Stalker With a Crush... whose mind was warped and powers derived from the same cosmic horror. Which he had just beaten.
 * Well, if it came down to defeating the entity that wants to destroy the universe, or keeping a promise that you made and just forgot due to death and rebirth (and fixing mistakes that you yourself made), what would you do?
 * "When I say Heart Of The Cards I mean Give Me Something Good."
 * could actually do this in the original series, but only after . Supposedly, anyone could pull that trick off, while the aforementioned character was just really, really good at it. (Good enough to, in fact!) Sort of undermined the whole "Heart of the Cards" thing from the dub, though...
 * As an inversion of the trope, Himawari from XXX Holic randomly causes bad luck to anyone who tries to become close to her, with the exception of few people: her parents and Doumeki. She can't control when or who it happens to.
 * In the Nasuverse, Marble Phantasm is the ability to interfere with probability to transfigure the surrounding world at will according to the user's vision of the world, limited to the scope of nature. The English name comes from a metaphor of picking a white marble from a bag of mostly black by making the chance of doing so 100%. In Tsukihime, Arcueid uses this to turn layers of the atmosphere in the corridor into a vacuum that shreds her target. (She was incapable of, for instance, distorting the floor.)
 * This is contrasted with the Reality Marble. A person with a Reality Marble would also have the ability to grab a white marble, by turning all the black marbles white. However, Reality Marbles tend to be limited to specific effects, as opposed to the Marble Phantasm's ability to basically do whatever the user pleases.
 * Vision of Escaflowne. The primary antagonists
 * of Saki. There are Born Lucky players who could get the Mahjong tiles they need almost all the time... and then there's her. She's not only Born Lucky, she can actually manipulate the luck of everyone around her so that no one else on the table could ever get a good hand unless she lets them.
 * Also, the titular heroine, Miyanaga Saki, who is quite clearly described by her to-be teammates in the first episode as having "superhuman luck" as if it were an actual superpower. Then again, considering the kind of ridiculous hands these people get, it probably is.
 * This is the power of Ania Fortuna of Asura Cryin. As a luck eater, she can remove or add to the luck of a person in the area by biting them. The uses for this are variable, from giving Tomoharu an edge in battle to making sure he's on the receiving end of pranks.
 * Horribly deconstructed in the first Tokyo Babylon OAV. Shinji Nagumo noticed he had such an extremely good luck that he survived several accidents: he became so smug that he actually started to set different accidents involving him and his work rivals/superiors. . . so that he'd as much get small wounds, but the others would end up dead. I.e., he tampers with an elevator which falls down its hole with him and the head of the enterprise inside then stops mid-fall; as a result, Nagumo gets a broken arm and the old man dies of a heart attack, setting Nagumo as a possible succesor to his director seat. Too bad the boss had hired Subaru Sumeragi believing that there was a curse in his company, so this puts Subaru and Seishirou in the case...
 * This is a good way to look at the Zero System in Gundam Wing, which can show someone all the thousands of different ways a battle can go and enable one to see the scenarios where they win.
 * In Tengen Toppa Gurren Lagann, the Anti-Spirals have access to missiles that alter probability to prevent the targets from avoiding or blocking them. This technology is thrown right back at them in the final battle; missiles that can't miss happen to be perfect for Attenborough's favourite tactic.
 * To clarify, the reason Attenborough can't miss is because he targets every single point of space-time at once.
 * If he could control it, this would be what Touma, from A Certain Magical Index, would have. He essentially suffers from unbelievable bad luck with Power Incontinence. This has a hidden advantage, however: He's so unlucky that his right hand has the ability to literally block any Psychic Power it comes into contact with by cancelling out the user's luck as well.
 * The villain One-Eyed Othinus, aka Odin, has the ability to have a 50/50 chance of success at anything she tries. However, she has no control over it, meaning she has a 50% chance of giving her foe a Curb Stomp Battle no matter how powerful they are or a 50% chance of losing to a wimp. Because Touma has very bad luck, when he faces her, she almost always gets the 50% chance of victory.
 * The main character in the manga Psycho Busters appears to have this, with things like pieces of the ceiling falling to intercept attacks or the floor collapsing under his opponents feet just before they attack. It turns out to be just highly precise subconscious time manipulation.
 * Mawaru Penguindrum's fifteenth episode reveals that has the ability to change fate in exchange for something important to the user.
 * Mawaru Penguindrum's fifteenth episode reveals that has the ability to change fate in exchange for something important to the user.

Card Games

 * Collectible Card Games like Magic: the Gathering frequently have cards whose effects allow a player to partially stack, reshuffle, or otherwise manipulate either their or their opponent's deck. (A classic Magic example of this is Portent.)

Comic Books

 * Trope Namer which comes from the signature chant (at least in the cartoon The Avengers United They Stand) of Wanda Maximoff - aka the Scarlet Witch - who pretty much launched this trope. It may seem like a pointless power, but she's the only person who can consistently beat Ultron.
 * And that's before it got kicked up to total omnipotence.
 * Spider-Man's Black Cat had the (latent) mutant ability to cause "bad luck" to anyone who threatened her or her friends, with the unfortunate side effect of giving her friends rotten luck, as well.
 * Also, when initially introduced, part of her schtick during a robbery was setting things up beforehand so that it would seem that those who chased her were falling prey to completely random acts of God.
 * In The DCU, the super-villainess Hazard causes bad luck for her opponents by tossing a pair of dice (that always come up snake-eyes).
 * In The DCU, villain/hero/villain again/hero again Major Disaster's probability-altering powers allow him to cause apparently anything that can be labeled a "disaster" e.g. earthquakes, meteor showers, power outages, heart attacks, etc. Not to mention an "entropy shield" that causes bullets and such to miss him.
 * Talisman from the Justice Machine comics had this power. One standard tactic of the team (much to Talisman's disgust) was to throw Talisman towards their enemies. This would in variably result in the bad guys guns jamming as they attempted to shoot Talisman.
 * Longshot and Domino have this ability.
 * In the "Ultraheroes" Affectionate Parody of superheroes story running in Walt Disney's Comics #701, Gladstone Gander, already Born Lucky, is upgraded to the ultrahero "Cloverleaf" with this power. He then engages the also upgraded Pegleg Pete in a Curb Stomp Battle.
 * Shamrock (Marvel's attempt at an Irish Captain Ethnic) is somewhere between this and Born Lucky. She's accompanied by ghosts that manipulate events in her favor in return for her helping them resolve Unfinished Business. Note that this isn't always a good thing--her fight with Deadpool in Marvel Zombies
 * Amadeus Cho is eventually revealed to have a variation of this power. When sufficiently charged up (usually via sugar), he can actually see the formulae of event probability, and pick or dismiss which ones he wants to happen or doesn't, essentially setting off Rube Goldberg Devices of reality warping. Especially fun when he uses it on telepathic opponents, as they can also see what he's doing, but most can't duplicate or even keep up with it.
 * This is the nature of protagonist Zayne Carrick's "special relationship" with The Force in the Knights of the Old Republic comics, revealed in the final arc.

Literature

 * The Ta'veren from The Wheel of Time series have this to varying degrees (which also varies arbitrarily over time), but they have absolutely no control over it and no way to turn it off. Things can get really weird across an entire city around them at times.
 * Moreover, the same power in fact pushes them (and those around them) towards their destinies, for better or worse. Not so much Screw Destiny as a superpower as You Can't Fight Fate.
 * The power seems to have specific effects for each of the ta'veren. Mat's power seems to directly tweak probability, one time actually . Perrin's seems to tweak people, making them say or do things they wouldn't normally do. And Rand just causes everything in a very wide area to go haywire just by being there long enough.
 * Late in the series, there are signs that ta'veren can have some control of their power and literally twist the Pattern of Ages to their will. Rand starts threatening to will people to death, and though he doesn't actually do it, it's treated as a real possibility. And it may also counter the Dark One's taint on the land itself. For example -.
 * This seems to have something to do with the ta'veren's intent. When Rand is despairing and verging on destroying the world himself, he stops causing any good events, only bad ones. After he gets some Epiphany Therapy, the opposite seems to happen.
 * Aornis Hades from the Thursday Next series had the latent ability to cause extremely unlikely misfortunes: being struck by lightning, or being crushed by a car jettisoned from a zeppelin. This is explained as some sort of entropy manipulation. It causes all manner of bizarre coincidences beforehand that can tip off the intended victim, but that's only useful if you know about it.
 * It can even be used in your favor: Thursday at one point tries to find a certain person's telephone number, but the phone book lists more than 50 people with that name. She just pierces the page with a pencil right before leaping out of the way of a car - and, of course the pencil hit the right one.
 * The Infinite Improbability Drive which powers the Heart of Gold ship, from The Hitchhikers Guide to The Galaxy.
 * As explained in the appendixes of the The Death Gate Cycle, Patryn and Sartan magic is based on modifying probabilities so that the outcome you want happens, instead of what was most likely to happen.
 * The magic in C. J. Cherryh's Sword of Knowledge books consists entirely of causing the target to have good or bad luck.
 * The main character, Bink, in the first Xanth book ''A Spell for Chameleon" had a magical ability never to be harmed by magic; he had no control of this power and the power always managed to make it look like his survival was purely by chance so for a long time everyone assumed Bink had no magic ability at all. The rationale for this subtlety seemed to be that if Bink's enemy's knew he was invulnerable to magic they would use non magical means to harm him so his own magic talent kept itself hidden.
 * Later books seemed to indicate that Bink's power grew from just protecting him from magic, to making him the luckiest person to ever live. Some characters speculate that his powers actually managed to manipulate the True Neutral Eldritch Abomination that serves as Xanth's God and source of all magic, and that his luck also partially protects his many descendants as well. Essentially, Bink's power is unconsciously causing the universe to play Gambit Roulette in his favor.
 * Magician Murphy's magical talent also in the Xanth series: "Anything that can go wrong, will go wrong." (He can direct this wherever he likes, so it's a lot more useful than the real-world equivalent.)
 * In Night Watch novels by Lukyanenko curses on people result in an attraction of bad luck to that person. Cursing is an ability even normal people can do - and is why the Light Others are so careful about swearing about someone doing something.
 * The Others can also look at their "probability threads", their possible fates in the next few hours and pick their paths accordingly. A conscious and inverted version of this trope, if you will.
 * In The Dresden Files, several villains can cast "entropy curses" which cause their targets to suffer convenient accidental deaths. Exactly what kind of accidental death is heavily influenced by who's casting the curse; when the caster has a practical, organized personality, the "accidents" are simple and unremarkable, but when cast by someone undisciplined and prone to dramatics, the curses tend to result in things like the target getting hit by a car... while water skiing. Or someone being crushed by a frozen turkey which fell out of an airplane. (The temperature sensor then popped while everyone was staring at the crushed body, resulting in a Crowning Moment of Funny in the middle of a fight scene.) To a lesser extent, all wizards are stated to have this going on all the time - it's how the Magic Versus Science thing works. Just by being near a complicated machine, a wizard makes random errors more likely to occur.
 * Justified the hell out of in Greg Egan's novel Quarantine. Something involving quantum mechanics, wavefunction collapse, and an "eigenstate mod." I could try to explain it more, but we'd just both end up confused. Unfortunately, since this particular gift is distributed as a body modification, chaos breaks out when a city's inhabitants receive the mod: almost every single citizen temporarily becomes a Reality Warper, and though the rest of the world is apparently unaffected, Reality Is Still Out To Lunch in that particular city.
 * The Lazy Guns from Iain M. Banks' Against a Dark Background worked by causing a unlikely event when you pulled the trigger on someone: instead of simply being shot, an anchor might fall on them and kill them. If shot at a ship, a tidal wave could destroy it.
 * In Tanya Huff's Keepers Chronicles series, the Keepers have the ability to alter reality by changing the probability that certain actions can or will occur. For example, the heroine can take her familiar, a talking cat, into a restaurant to eat by changing the probabilities that anyone inside the restaurant will notice anything out of the ordinary. Or, she can get a noisome person to vacate her presence by increasing the probability that they need to get to the nearest toilet, immediately.
 * Fitz, from Robin Hobb's Farseer and Tawny Man trilogies, is a Catalyst. A Catalyst is periodically born in conjunction with a White Prophet who can see possible futures. The Catalyst alters circumstances just by existing, causing the possible futures the Prophet can see to multiply and better enable him to guide the world down the right path.
 * The titular protagonist from Leven Thumps is an offing, which means he has both the power to see a bit into the future and manipulate it, although he can not always control how he manipulates it.
 * The Chaos Weapon by Colin Kapp is a Wave Motion Gun with this capability: if something bad will ever happen in the target area, the Chaos Weapon can make it happen NOW. Lightning strikes, dams giving way, earthquakes.... And at least some of the power needed to move the event from its proper place in space-time winds up increasing the violence of the event.
 * In Wolfgang Hohlbein's Die Rückkehr der Zauberer (Return of the Sorcerers) having luck is the protagonists main ability. Examples of use are him finding a pack of zigarettes, manipulating cards (making him always predict the wrong card), or turning all traffic lights green when he drives with over 60 mph through the city.
 * Luna of the Alex Verus series suffers a curse that causes her to essentially steal luck from those around her, causing misfortune to anyone who crosses her path in exchange for being essentially immune to random accidents herself. If that sounds handy, that's because it's actually a variant on a defensive spell: The curse is that she can't turn it off, making long-term relationships extremely difficult.
 * Harry Potter gives us a potion called Felix Felicis, a potion which will make a person phenomenally, impossibly lucky. There is no chance of "Felix" screwing up and almost everything will go right for the user. In fact, it's not even limited to mere probability, as Harry actually goes out of his way to do something that was not his plan simply because it felt like it was the right thing to do, and it worked. In fact, it is wizarding law that one cannot use whenever they're supposed to be making a bet, have a Quidditch, are taking a test, etc. The drawback comes in in that it is a dangerously tricky potion to make and it is dangerous to use it more than very sparingly. Also it is stated that luck can't do everything, . The tie in book, Fantastic Beasts and Where To Find Them, gives us the exact opposite of Felix with the Mackled Malaclaw. It has a venom which will make the victim impossibly unlucky, and the book even warns that a victim should cancel any bets, duels, tests, etc. as they are sure to go against the victim.

Live Action TV

 * In Red Dwarf, this power is bestowed upon anyone who contracts the good luck virus. Lister uses it twice in the series to perform such feats as finding discarded fully functional weapons and correctly guessing a security password on his first try.
 * Chance Harper's main ability from the old FOX show, Strange Luck.
 * Trance from Andromeda has the power of luck, and if made to guess, will usually guess correctly despite extraordinary odds. Also, her presence might cover what in other TV shows is taken for granted: none of the main characters die, and the Andromeda doesn't explode.
 * In a later episode, it turns out that she actually is able to see the multitude divergent futures and follow them through to where the main characters don't die. It gets really burdensome on her.
 * The leprechauns of Charmed can bestow good or bad luck on someone. The episode "Lucky Charmed" involves a demon who is threatening the community of leprechauns, and ends with this demon getting hit by a meteor.
 * In the Star Trek Deep Space Nine episode "Rivals," the central guest character obtains a device from a dying alien that allows probability to be altered. He then somehow manages to create larger versions, which then go on to wreak havoc throughout the station. When the crew figure out what's going on, they destroy the devices, which are then never heard of again.
 * An episode of Supernatural revolved around a rabbit's foot that was stolen from one of John's storage units. The foot would bestow great luck on its owner...until they lost it, after which their luck would be nothing but awful. Death was soon to follow.
 * And it was hilarious. Poor Sam.

Tabletop Games

 * The World of Darkness games have a couple of examples:
 * Mage: The Ascension covers this power under the Entropy sphere. In Mage: The Awakening, it's covered under Fate.
 * New World of Darkness-only examples:
 * Changeling: The Lost has the Contracts of Hearth, powers that affect a person's luck with the caveat that they can't be used too much. The caveat responds to the magnitude of the power -- a power that impedes another person can't be used on them more than once per day, a power that blesses another person's action can't be used for the exact same purpose twice per day, and a power that grants a truly monumental success can't be used more than once per year. Attempts to go against these provisions backfire. Badly.
 * Vampire: The Requiem has the Bohagande bloodline, with the power to steal others' luck for their own use.
 * According to some supplemental material the Lovecraftian god Nyarlathotep seems to have the ability to tweak probabilities to go to his favor, although it only seems to apply to small-scale stuff. His real power is being a Shape Shifter Chessmaster (and, you know, a god).
 * In both Warhammer universes, Tzeentch, the god of Gambit Roulette, has it as part of his portfolio. There is a reason his greater demons are called "Lords of Change".
 * In Warhammer 40000, the lowest-level psykers have a great deal of good luck. Higher-level ones may be able to influence it.
 * Complete Scoundrel gave luck feats and even a prestige class based upon them to Dungeons and Dragons.
 * There's also the Fatespinner (Song and Silence, later updated in Complete Arcane) and Luckstealer (Races of the Wild) prestige classes for spellcasters that like to manipulate fate.
 * For the gods in Deities and Demigods, the salient divine ability "Power of Luck" is basically this trope, and its strength is proportional to how many divine ranks the deity has.
 * Magic in the Maelstrom gaming system worked by warping probability in this way. There were different grades of spells, ranging from "likely" through "unlikely" and "wildly improbable" to "completely impossible."
 * The original 1980's Marvel Superheroes RPG had the power of "Luck" - in a game where everything was determined by percentile dice, this allowed the character to ALWAYS take the higher die as the 'tens' digit, making it INORDINATELY powerful to have.

Video Games

 * Nell (and to a lesser extend, her little sister Rachel) has this as her power in Advance Wars; her units are naturally more likely to score extra damage, and her CO power takes it Up to Eleven, allowing such impossible feats as infantry taking out a platoon of Megatanks.
 * Fortune from Metal Gear Solid 2 is said to have this power, but the real explanation is something else entirely. (Maybe.)
 * The "Super Luck" ability which some Pokémon have.
 * In Sid Meiers Alpha Centauri, sufficiently advanced factions can armor their units with "probability sheaths" in a practical application of Probability Mechanics.
 * In Fallout, "Luck" is one of the seven Base Stats, with this exact effect on your personal actions. Taking the "Jinxed" perk would cause both you and everyone else to suffer far more critical failures and lower your Luck stat, Fallout 2 upped the ante with Pariah Dog, who drops your luck to 1 once he starts following you around. Since all of this can stack, creating a Jinxed character with 1 Luck and Pariah Dog as a pet can turn the PC into a walking disaster area.
 * Creating a character with 10 Luck (the maximum) and the Jinxed trait creates a PC who is a walking disaster area, but is never touched by it themselves. Angel walking through the valley of death style. This is awesome.
 * You'll still critically miss much more than without the Jinxed trait (not perk), but simply because a gang of enemies have more turns that you, they'll be bearing the brunt of the fails. As such, a good tactic is to go solo and NOT ATTACK while enemies lose their ammo, destroy their own weapons, and break their own limbs trying to attack you.
 * Fallout 3 and Fallout New Vegas lessened the effects of luck considerably, but it does determine your success at winning casino games in the latter. Low-Luck Couriers can say goodbye to their caps (6 or less), while High-Luck Couriers will be banned from a casino in ten or fifteen minutes for winning too much.
 * Kingdom of Loathing has the Black Cat familiar; which causes everything to go wrong for you. If you beat Bad Moon with this as your familiar every single fight, that difficulty level is permanently unlocked.
 * There is also the Black Cat Tonic which temporarily lets you spread bad luck to enemies; upping their fumble rate and never letting their critical.
 * Opposing that is the Ten-Leaf Clover. Whn you enter an area with a Clover, it initiates a Clover Adventure if there is one in that area. Clover Adventures provide very good items, buffs, or stat points.
 * The Gambler class in some Final Fantasy games.
 * Milfeulle Sakuraba has what could be considered an unconscious version of this trope, only turned Up to Eleven. When her luck is good, it's insanely good (for example, her Establishing Character Moment in the first game has her winning the grand prize in a convenience store lottery five times in a row); however, when her luck is bad, it's horribly bad (a picnic being ruined due to a fire alarm being tripped, followed by the Cool Ship she and her crewmates serve abord warping out in the middle of an enemy fleet, followed still by her personal starfighter's engine crapping out on her).
 * Touhou Project has this as either an explicit or implicit superpower of several characters:
 * Reimu implicitly uses this as her ultimate power - in spite of technically being totally outclassed in terms of raw power to the actual deities or Reality Warper enemies she fights, she uses her "Intuition" to frequently evade all harm from things that should flatten her to a paste. Of course, her explicit power is "merely" a low-level Reality Warper power, which may certainly help in this regard.
 * Remilia Scarlet has "Manipulation of Fate" as a (largely undefined) superpower, although she generally just uses brute vampiric strength in combat. It is implied, however, that she can manipulate destiny to ensure such things as the survival of her human friends, or the success of the machinations of the absurdly involved Batman Gambit plots of the likes of Yukari. It's unclear if she even knows she has this power, and if it is conscious or unconsciously used. One in-story rumour says she changed the fate of her maid by giving her a different name.
 * Both the goddesses Hina and Suwako are curse goddesses. Hina is a born goddess of misfortune that can inflict bad luck upon people to the point where they suffer a Necro Non Sequitur. However, she generally likes people, and instead grants good fortune by eating the misfortune of others. Suwako gained curse god powers by bringing powerful curse gods under her control, but generally uses her powers to help others, largely because she needs people's faith in her to continue to exist, and as such grants good fortune and miracles in exchange for faith. Both, however, use their curse powers as weapons when in a fight.
 * Then there's Suwako's priestess Sanae, who explicitly has the power to cause miracles. Like your miraculous defeat at her hands.
 * And last but certainly not least is Tewi the rabbit youkai, who has the power to bestow good luck.

Visual Novels

 * Bernkastel, the Witch of Miracles, in Umineko no Naku Koro Ni. Flexing her full powers (as she does for from the first Core Arc onwards) favors game pieces with lucky "coincidences" worthy of any Mary Sue.
 * According to background infos of Tsukihime, this is how Marble Phantasms work: their wielders take something that is extremely unlikely to happen and raise the probability of it happening that very instant to 100%. E.g. Arcueid at one point manipulates the Brownian motion of air particles inside a corridor to form thin interspersed layers of dense air and vacuum, ripping an enemy to shreds when air pressure normalizes again.

Webcomics

 * In Sluggy Freelance the Fate Spiders' ability to manipulate the Web of Fate is the inverse of how this power often works. They have incredible amounts of precision over which events they change the probability of, but how much they can alter probability is severely limited; they can only affect the outcome of events when the odds of one thing happening instead of something else are almost 50/50, like making someone decide to get pizza to eat instead of burgers. They have to make use of their immense knowledge of destiny and lots of For Want of a Nail moments to accomplish anything of significance, and even then someone who's Immune to Fate can still muck it up.
 * In Homestuck, Vriska (after attaining ) gains all of the luck. All of it. She literally has the ability to steal luck and cause misfortunes (such as a floor collapsing underneath her opponent), or to manipulate random events like coin flips in her favor. She's convinced that this makes her more powerful than any of her teammates and even the Big Bad of the comic, because it is impossible for her to lose.
 * Clover of The Felt, a rival gang to The Midnight Crew, has luck that in theory makes him very difficult to hurt (he states that a gun pointed at him would jam). Diamonds Droog gets around this by swatting Clover with a newspaper -- you don't have to be that unlucky to be swatted by a newspaper, it's kind of a grey area.
 * Although Cans, whose power is to be able to literally punch people into next week! Bursts in immediately. Yeah...
 * In Erfworld, one type of caster is a Luckamancer. At one point a Luckamancer explains his magic by comparing units to dice. When one receives his boost, it only rolls max for the next combat it's in.
 * In Darths and Droids, one of the Jedi abilities is "fate manipulation", which, in game mechanics terms, allows a player to reroll a dice. The characters use this to varying effectiveness throughout the games.

Web Original

 * Lady Luck of the Knights of Norfolk is an active probability manipulator.
 * Domino is a slightly clairvoyant martial artist who can see the future just enough to let her avoid bad choices. Her teammates simply assume she's incredibly lucky.
 * Hazard, like Lady Luck, can manipulate probabilities directly. Unlike Lady Luck, he does so to commit crimes.
 * Several side characters in the webfiction Whateley Universe have this ability to some extent. Hazard (apparently a common name for these types of characters) also senses when unlikely events are about to happen, which is usually a sign to get the heck out of the area. Kismet has magical abilities and the ability to teleport short distances. When she teleports, local probability goes haywire: an opposing fighter is either going to slip on something or score an easy one-punch knockout. Risk likes to use his ability to play pranks and cheat at games like pinball. To say nothing of the cute little disaster that is Clover of the Three Little Witches (she's a wizard in the making all right, she just has this power on top of that).
 * The school's administration, incidentally, generally does its best to keep these 'probability warpers' separated -- in different cottages, if possible -- because of the risk of their powers heterodyning and spontaneously creating wholly unpredictable events.
 * In the Dr. Horribles Sing Along Blog fanfiction A Shiny New Australia,

Western Animation

 * Jinx of Teen Titans has this as a power, although she's only capable of creating bad luck. Of course, this usually involves wanton spontaneous destruction.
 * Fry's lucky seven-leaf clover in Futurama bestowed incredible luck on its owner, allowing them to be immensely successful at anything they did. Maybe.
 * The Anti-Fairies in The Fairly Odd Parents are the complete opposite of fairies in the fact that they roam the world causing bad luck to people, reinforcing many popular superstitions such as spilling salt, walking under a ladder, breaking mirrors, etc. Unsurprisingly, their favorite day is Friday the 13th.
 * The black cat from the classic cartoon "Bad Luck Blackie" can cause random objects to fall on anyone whose path he crosses; he actually served as the inspiration for Black Cat's bad luck power (see above).
 * Equinox from Batman the Brave And The Bold has done feats like make a tree branch break and fall on Batman.

Other

 * Bionicle
 * Toa Jaller has the Mask of Fate, allowing him to do exactly this.
 * Toa Nikila has the Mask of Possibilities, which is similar to the Mask of Fate. The main difference is that while the Mask of Fate is limited to allowing the wearer to perform at his maximum physical capacity by altering probability, the Mask of Possibilities can make any event more or less likely to happen.