Feedback (Ben 10 Omniverse) is considered as Ben's favorite alien and has defeated most of Ben's foes and has more wins than loses.
You heard her (DC Comics).
Wonder Woman (DC Comics) vs. The People's Republic of China military
Batman (DC Comics) teaches a valuable lesson to Green Lantern
Storm (Marvel Comics) the OG knife fighter of the X-Men
There's a reason why he's called Invincible (Image Comics).
Got your Nose!!! (Marvel Comics)
Wolverine (Marvel Comics) Goes Fishing.
Old Man Logan (Marvel Comics) doing what America couldn't.
Driving with Daredevil (Marvel Comics)
Judge Dredd (2000 AD) is your judge, jury and executioner if need be.
Marco Diaz (Star vs. the Forces of Evil) is a student in the Tang Soo Do discipline of karate and, as of the eponymous episode, has a red belt. He is very capable of using karate chops, kicks, and punches to battle monsters as effectively as Star. He is able to use karate with potentially lethal force as demonstrated when he cuts off Tom's hand with a karate chop and punches a hole through Toffee's chest.
Sosuke Aizen's (Bleach) power and fighting skills allow him to defeat the strongest Shinigamis, even Genryusai Yamamoto with his tactical genius.
Vegeta (Dragon Ball franchise) has pulled of badass feats such as holding his own as a Super Saiyan 2 against Kid Buu, a monster that defeated a Super Saiyan 3 without seeming to suffer any fatigue, and even made Buu back up in fear of his resilience and determination.
Like most Abnormals, Medaka Kurokami (Medaka Box) can achieve incredible feats, such as catching cascade of bullets with her mouth.
Capone Bege (One Piece) can defeat the most powerful enemies with his tactical genius.
Raizo (One Piece) is an awesome ninja.
Germany (Axis Powers Hetalia) can break a spoon with his bare hands, along with other things.
Jotaro Kujo (Jojo's Bizarre Adveture) is an extremely cool individual, able to keep his composure in even the direst of situations. A gambler trying to steal your soul? An evil assassin holds your granddad as a hostage? A immortal vampire trying to kill you? CALL HIM.
Barney Stinson (How I Met Your Mother) has gone past what is possible, to the place where the possible and the impossible meet to become... the possimpible.
Zohan (You Don't Mess with the Zohan) uses his power in the most badass ways, such as folding his enemy to pretzel or putting piranha in his swimsuit.
Mr. Smith (Shoot' Em Up)
The MacManus brothers, Connor and Murphy (Boondock Saints films) are able to simultaneously fire two Desert Eagles without recoil, seem to have unlimited ammo and survive against all odds by pulling off seemingly impossible feats that border on dumb luck.
Ashley J. Williams (The Evil Dead series) has survived countless demonic related events, time traveling to medieval times, demonic possession, and fighting his own evil clone.
Not only can Weird-Ass Guitar Guy (Channel Awesome) play a multi-necked electric guitar that can shoot dinosaur missels, but he wears a blindfold because his body is full of so much testosterone that his eyes literally shoot shark-shaped explosions.
Chuck Norris... 'nuff said.
Duke Nukem (Duke Nukem franchise) kicks alien ass and looks good doing it.
Juvie (Valkyrie Crusade) is a badass.
Various human characters such as Leon Scott Kennedy (Resident Evil franchise) are able to perform difficult acrobatic feats and survive insurmountable damage that would be fatal to normal people.