Heroclix both Franklin Richards and LiAnn were given the God Amongst Pogs status because of their low cost, their seeming inability to do damage and the anecdotal stories of them knocking out super villains and heroes several orders of magnitude above their power level.
Alfred was also known as the first God Amongst Pogs and would routinely win tournaments if run correctly. But to be fair it was a representation of Alfred.
Some Warhammer 40,000 fans make Commissar Yarrick out to be the series' answer to Chuck Norris. Two of their claims:
The God-Emperor of Mankind is merely warming Yarrick's seat.
The Tyranid extra-galactic Horde of Alien Locusts encroaching on human-controlled space was a set of splinter groups fleeing from Yarrick's own extra-galactic adventuring, which had previously destroyed the majority of their forces. Or, should they say, "fleeing".
The Orks pass along rumors of Yarrick being able to kill with a glance. Yarrick simply thought "Good idea" and installed a fucking laser into the bionic eye made to replace the original he lost fighting Orks. This is after he also had his hand replaced with a Power Klaw, usually reserved for Ork Warbosses about three times his size. This is not a claim. This is actual, in-game canon.
Within the W40K 'verse itself, we also have Commissar Ciaphas Cain, HERO OF THE IMPERIUM, whose reputation for heroism has grown to the point that one Imperial cult has actually proclaimed him "a physical manifestation of the God-Emperor's Will". Of course, because Cain is an Accidental Hero who is actually a Dirty Coward, the whole thing is played for laughs.
Also Gunnery Sergeant 'Stonetooth' Harker, a Catachan who carries a heavybolter by himself and is said to chew glass instead of tobacco.
The OotS forum is attempting to turn Eldrad Ulthran into the man who caused everything in the universe, along the lines of "God created Earth, Chuck Norris created God, Rick Wakeman composed Chuck Norris, and Eldrad Ulthran gave Rick piano lessons." 1d4chan depicts Eldrad as a omniprescient dick who uses his psychic powers to be an annoying Troll to both his enemies and his allies.
The speed with which this meme has infiltrated the fandom is quite astonishing. It would have taken some sort of tactical genius t- CREEEEEEEEEEEEEEEED! Ursakar Creed gets treated as a brilliant Mary Tzu who can hide just about anything, anywhere. Hiding Leman Russ tanks behind lampposts, hiding squads of Stormtroopers in the reader's bathroom, disguising a Baneblade as a therapist, you name it.
Then we get to his Cousin, Lord General Castor (of Dawn of War II Fame) who is slowly turning into this trope, it helps that his trophy wall is the largest and most complete archive of all Tyranid species that have been encountered by the Imperium so far. His Badass Mustache is one of the Imperium's mightiest weapons.
In-universe example with Duke Sliscus. The Dark Eldar, who can only be described as a ProudSpace PirateRace Guy], view him as an absolute legend. And given how some of his more epic moments include stealing three flagships from an Archon just to show off and then kicking his ass when he and his forces try to get them back, and completely owning fellow Memetic Badass Lukas The Trickster in a battle of wits, some players can't help but agree.
Since the Horus Heresy book Legion, absolutely everything that has happened or ever will happen ever is an Alpha Legion plot.
Gotrek is generally considered Memetic Badass among Warhammer fans. Dwarven (dwarves are most badass race in whole setting) troll slayer (troll slayers are most badass of all Warhammer dwarves), most (or, depending on perspective, least) successful of all dwarven troll slayers.
To some, every Chaos invasion of the Empire to date has crossed the Sea of Claws instead of going through Kislev because the Norscans are scared shitless of TsarinaKaterin.
Exalted's Michael Goodwin, aka Nephilpal, is the true designer of the system, who died in the First Age but will return to save us all from crappy quality control.
Also from Exalted: the Mirror Flag. The greatest liar in Creation. She canonically rewrote her own history because it wasn't epic enough for her. Less canonically, everyone in Creation is the Mirror Flag in disguise and doesn't know it.
Demetheus, a.k.a. DEMETHEMANIA! Wandering badass righter of wrongs with the comportment of Tom Joad and the strength of ten bulls.
Many, many people in Legend of the Five Rings, but the greatest of them is Toku. Following his elevation to memetic badass-hood, he was elevated by the tournament wins (which determine storyline in L5R) to canon badass. Originally a peasant acting as a samurai, Toku ended up becoming a recognized samurai, hero of two wars, captain of the Imperial Guard, founder of his own clan, Empire-renowned legal and moral authority, and, posthumously, a god. All of this because people thought a free, unaligned character designed to be fed to demons was pretty funny.
Yoritomo was declared by Word of God to be the greatest warrior in history. Bear in mind that this is a setting that thinks nothing of having a god and his son duke it out in Hell for centuries, killing anything that dares to try to interrupt. There's even card art showing Yoritomo being offered the throne by another god, and Yoritomo walking away while giving her the finger.
Simultaneously subverted AND played straight with Bayushi Tangen, his heir Kwanchai, and their students in the Dark Sword of Bitter Lies, both in story and out. Created as a parody of Mary Sue powergamers, the Bitter Lies technique revolves around three things: luck, insanity, and loyalty to the Scorpion Clan. Without all three, the methods are worthless, lethal only to the chump trying to use them. With all three, the storyline presents the characters as literally unkillable: to date, no Bitter Lies swordsman is confirmed dead. The closest thing to an exception is Kwanchai, who went on a Roaring Rampage of Revenge against the very dimension of Roaring Rampage of Revenge. It took Word of God to convince players that Kwanchai didn't destroy the dimension outright, and even then, nothing's stopping the writers from saying he's Not Quite Dead.
As a bonus, simply meeting Kwanchai was enough to balance the kharma of Bayushi Shoju, generally considered the greatest traitor in the empire's history. Shoju has since reincarnated, and is set to lead the Scorpion to victory, and to redeem his name in the eyes of the empire.
In-universe example from BattleTech. Kai Allard-Liao is widely regarded to be one of the best pilots of his generation. In a simulated combat test on the home planet of Wolf's Dragoons, he managed to defeat five elite opponents, including his trainers, his own father, and his liege lord, in a trial where defeating three was a mark of exceptional skill. The test was an analogue to the Trial of Position of the Clans—three kills would have made him the equivalent of a company commander, four kills the equivalent of a major. Five kills effectively made him the equivalent of a front-line regimental colonel and was unheard-of in Inner Sphere or Clan space. When he was stranded behind enemy lines, the Jade Falcons who controlled the planet thought it only just and fair to send fiftyPower Armor wearing Super Soldiers to apprehend him because of his reputation. That he manages to kill one in hand to hand combat is a feat in and of itself, given that his enemies were eight feet tall and five hundred pounds of muscle. After that, they actually start the bidding war to capture him in armor. Upon encountering the Falcons later in an Enemy Mine situation, one of the Falcons, after hearing the details of the aforementioned test, murmurs something to the effect that three Stars (seventy-five) of the Super Soldiers in armor would be required for a fair fight against Kai. That is an entire Clan Battle-Armor infantry company, and is considered the formation-equivalent of an entire Drop Ship-load of fifteen Humongous Mecha. In all fairness, at that point in the narrative, Kai had over fifty kills to his credit just on the Jade Falcons alone, as the Falcons themselves point out.
To clarify three things:
When the above troper says in armor, he's not talking about armor as we know it today. Elemental Power Armor can soak damage that would kill 10 unarmored men, has a jetpack that can carry it 90 meters per jump, and carries 3 weapons, an anti-personnel gun (think an Uzi strapped to your arm), a twin missile pack with an extra reload, and a modular weapon, either a MG (.50 Cal equivalent), flamethrower, or a laser.
The entire bit with Kai and the elementals happened about a month after Kai destroyed an entire cluster (3+ Trinaries of 15 mechs each) in a single go, in one of the greatest bits of combat theatrics I've ever read. He planned an ambush in a canyon, setting explosives on both cliff faces, but the men who were to set of the explosives were killed by some of the aforementioned Elementals. So he marches his mech, which was out of ammo and had lost all its laser weaponry, now only armed with a Hatchet, into the canyon and challenged the enemy commander to single combat. This allowed him to get right on top of the entire enemy formation. Then he stripped out the containment systems on his mech's fusion engine and ejected. The resulting explosion set off the explosives, burying the entire enemy cluster under thousands of tons of rock.
Kai's Career spans 25 years of nearly constant war. I could add a half dozen other stories about him and it still wouldn't do him justice. IIRC, when he finally is killed, its because the city he's in is bombarded from space.
Kai shot Vlad Ward, Khan of the Wolves, out of his 'Mech despite a twenty-ton weight disadvantage during the Great Refusal, the fight being horribly onesided in Kai's favor. He became Champion of Solaris, a world whose entire economy is based on 'Mech duels, in a single season, defeating most of the best warriors in the Inner Sphere. His canon record has only two draws and one defeat. Only one of the draws was on a real battlefield, where a Clan warrior sacrificed himself to push both their 'Mechs off a cliff into water several hundred feet deep. Kai survived. The other draw was during a simulator duel against one of the other best pilots in the setting, Phelan Kell: they shot each other's 'Mechs to ribbons and both had to eject at the same time. The only time Kai has been confirmed to have actually lost was in a reduced-power weapons combat against Morgan Kell, who has either supernatural powers or some kind of lostech device that prevents his 'Mech from being properly targeted by anyone.
Three words: Old Man Henderson. This... gentleman, has a legendary reputation among Call of Cthulhu players. Originally the brainchild of a player stuck in a brutally grimdark campaign with a bad GM, Old Man Henderson was a heavily Min Maxed Schizophrenic Scotsman who claimed to have fought in Vietnam (he didn't; he would've been far too young to sign up at the time) who joined the party because he wrongly believed that some cultists of Hastur were responsible for stealing his garden gnomes. His finer moments include dropping a Yacht on a penthouse full of Cthulhu cultists, killing several cultists (along with every other Player Character in that session) with a tanker truck full of C4, taking out a Shoggoth single-handedly with his trusty shotgun, and permanently killingHastur by luring him into an ice rink filled with explosives and detonating them. And that was how Old Man Henderson won at Call of Cthulhu.
Then he resurrected himself (Referred to as "Young Old Man Henderson") and Hastur with the help of Nyarlathotep, who got to have all of Hastur's power out of the deal, provided that the resurrected Hastur (now Heather) never reclaimed it. Henderson helped her reclaim it, sealed it in an amulet, then escaped to a parallel universe where Nyarlathotep couldn't touch them. This happened in a follow up campaign.