We are introduced to the main character of the online Irish comedy series I Am Fighter like so:
Barry: My name is Barry "The Blender" Henderson. Now, they call me "The Blender", because if you get within reach of me, I'm gonna turn you into a paste.
Naturally, it turns out that he's a woefully inept amateur Martial Artist.
Thomas "The Tanker" Smythe tells us that his nickname comes from the fact that he'd walk around thinking people were shouting "The Blender! The Blender" when in fact, they were shouting "You bender! You bender!". Which, as he helpfully informs us, is "A derogatory term for 'faggot' ".
The Crinoverse has a lot of these, but one comes from the end of the Chicago Avengers when Indomitable faces a fallen Chosen One, Mandragora. "My name is James Bennet. I am Indomitable. Know that I face you without malice or hatred, but I will defeat you all the same."
Ilivais X is FULL of these, most coming from Seyne and Mille, the latter prone to these nearly every day.
“IRIANAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA! HEAR MY CRIES! HEAR MY SOUL! YOUR AGONY IS OVER, YOUR SUFFERING IS OVER! I STAND RIGHT HERE BEFORE YOU, NOT HIDING IN THE STEEL FLESH YOU GAVE ME, NOT ANYTHING BUT MYSELF! AND I SWEAR, I WILL SAVE YOU JUST LIKE THIS IF I HAVE TO! I WILL NEVER DIE, NOT UNTIL YOU STAND BY MY SIDE! YOUR DAYS OF HATE AND REGRET AND SADNESS HAVE CONCLUDED! WHEN THE SUN RETURNS TO OUR SKY, OUR NEW LIFE BEGINS, OUR AGONY WILL BE ERASED, AND THE WORLD WILL BE OURS! ...So please...wait for me..."
Danya: Let's get one thing straight. The mafia, the US Government, even MADD - none of those organizations can scare me, and none can even touch me. The mafia wants to have a go at me, they can go ahead, but they'll have to find me first.
And of course, Linkara's from Silent Hill Dead Alive 5:
Linkara: See, I'm not some pretty boy with marital problems. I don't have some confused psyche or unresolved parent issues. You're not dealing with a Silent Hill protagonist here. Time and again, someone got it into their head they could defeat me. Time and again, they beat me down, knocked me out and tried to make me give up. You come at me with insecurity, self doubt and angst? You try to make me doubt who I am? I am the man who defeated Pyramid Head. I am the man who conquered Countdown. I am the man who fought off the Vorsoth and destroyed Mechakara. I am the liberator of Kickassia. I am a Star Fleet captain. I am a Power Ranger. I'm That Guy with the Hat. I am Linkara. (Illusions fade) Who the hell are you?
Apparently, Freeza has heard (nearly) every Badass Boast known to man - he even keeps track of how often he hears them (which is something of a Badass Boast in it's own right)! This changes when Goku tells him "I'm gonna deck you in the schnozz!"
Walter: Hello. My name is Walter C. Dorneaz, ex-vampire hunter and butler to the Hellsing organization. I answer the door, I clean up the estate, and I take out the trash. And I also kill self-entitled little twats like yourself.
In Bleach Ment, Ichigo delivers this... particularly bizarre one:
Ichigo: "I am the orange in your Fruits Basket, the Punk in you electronic amusement gallery, the ass that has bad written all over it. Ichigo Jason Statham Kurosaki!
The Global Guardians PBEM Universe. A Tarot Sword shoots Stone in the back of the head with a point blank .357 Magnum. After the bullet ricochets into the ceiling, Stone's response is to turn around... slowly... and growl, "If you ever... ever shoot me with that pistol again, and I ever hear about it, I'm going to rip your eye out of its socket and skullfuck you!"
In Samurai Senshi, Orochi delivers a nice one to the Mizusan: "You know not to whom you speak. I shall tell you. I am Orochi, the Kikuchin-Ryu. I am the viper that wields the deadliest rokushakubo known to man: Himehabu. Come, Mizusan, and discover how venomous my bite can be!"
When asked to provide his title before entering the arena, Torq of Critical Hit: A Major Spoilers Dungeons & Dragons Podcast launches into a long list of his accomplishments, picking up in volume and intensity as he goes.
slowbeef: "[laughter] YO, THIS SHIT, THIS KICKS LP HOT, SON! I AIN'T GONNA DIE, 'CAUSE IT'S A WASTE OF MY TIME! LUIGI, YO!"
Essentially the purpose of Epic Rap Battles of History. When they aren't knocking down the competition, the rappers are bragging about how great they are.
In a Mortal instruments RP forum run by Shadow Angel Demon, Osiris attempts to kill Umbra repeatedly. His actions are justified since Umbra is the only good demon to exist and the rest of his kind has an extremely bad reputation for commiting heinous deeds that even the foulest of humans wouldn't do. When Osiris is joined by Iliana, this exchange ensues.
Illiana lunged towards the Greater Demon, ignoring Orisis' claim that he had it. She threw a couple of her Runed chakras at the Greater Demon, before looking back at Ethan to make sure he was alright, because after all, he was her first priority.
Illiana smirked dispite herself; she never listened to anyone. "Whatta you gonna do about it if I do?" she twirled the chakras between her fingers, itching to throw them at him again, but this time, with more force.
Illiana looked unfazed. "I'm not Osiris." She laughed and ran towards Umbra, blade drawn and runes shining, giving her angel blood an intricate light that shone through her skin, one that normal Shadowhunters don't have, Shadowhunters that didn't tamper with ancient runes.
"Honestly. Does an enemy with thousands of years of combat experience mean nothing to you?" Umbra raised a hand at the three of them, and black and purple air forcefully shot from his palm, with enough force to knock Ethan and Osiris off their feet.
This continues for a few more minutes until Umbra loses patience and tosses Osiris through a wall, and then the two of them stop attacking him. He goes on to explain the real threat.
In Worm, Alexandria has an excellent one at the beginning of Cell 22.4 and spends the entire first half of the chapter proving it.
Alexandria: Threats is the wrong word. But English is a limited language in some ways. There’s really no word to articulate what I mean. A threat with a measure of inevitability to it. A promise? Too feeble. People break promises too often. A curse? A malediction? Too… magical. An oath? The connotations are wrong. When I say I’ll do something, I make it happen.