Such as Adam Dodd going ballistic on Cody Jenson near the end of V1, who he has every reason to want dead.
Sailor Nothing: although Himei usually just wills her opponents into non-existence, she has been known to tear them apart with her bare hands if put under sufficient emotional stress.
While it is debatable whether Nist Akath of Dwarf Fortress falls under this or Video Games, the scene where Ironblood is betrayed by the nobles certainly springs to mind. Ironblood is poisoned by the nobles who are servants of an evil god, stripped naked, and thrown into the arena he himself ordered costructed. Then, to kill him, they release a hydra to kill him. While naked, poisoned, and vomiting, Ironblood kills the Hydra with his bare hands. By crushing its skulls. Then, he climbs out of the arena, and... well...
"As he watched the dwarf crushed his wife's form, he came to a sudden, horrid realization. Ironblood didn't use an axe because he needed it. He used it to be kind. And right now he wasn't being kind."
Badfic is so horrendously bad that unstoppable rage is a common reaction for Protectors of the Plot Continuum agents, especially when a favorite canon character is threatened.
Parodied in Linkara's review of Wolverine: Adamantium Rage.
Caboose tries to intentionally invoke this in himself when he and Sarge are trapped in a bizarre land of eternal war in Red vs. Blue. 'I am Michael J Caboose ... and I HATE BABIES!' Followed by 'Hurk! Blagh!' repeatedly.
Comes back in Season 10; as the Blood Gulchers are lining up for a battle, Church says he needs Caboose to get a little angry; Caboose replies that he forgot how to do that. Church helps him remember, and Caboose charges headlong through a massive group of Tex copies.
From The Gamers: 'Barbarian rage! Blood, death, and vengeance!'. Success rate? 1 for 2.
And in 5, Dust does Snowball one better after killing him under the influence of the Psycho Serum that Smoke had injected into him by completely devastating Smoke's army of mooks, wrecking his helicopter gunship as he tries to get away and then sending the bastard right through its rotor blades.
In Fine Structure, a series of otherwise normal humans acquire Flying Brick powers. In each case, for the first 15.8 seconds after getting their new powers, they are stuck in an absolute berserker rage wherein they immediately attempt to obliterate anything and everything around them. Since they also perceive time at an accelerated rate, this gives them long enough to kill millions of people if the local population density is high enough.