I think granny was
Also, Warmaster Horus.
Though, Horus would probably be able to beat her down in no time since he has superhuman strength. Hell, anybody from the Adeptus Astartes older than 50 years can probably do the same.
And uh... That rock guy that can explode himself in the New X-Men. Seems he's almost impossible to kill. Oh, and also Mercury. Laura aka X-23 maybe? Wolverine?Shiro
vs Red is a no-brainer, too.
Too many to list them out, so there. Red is not invincible, not created to be an actual monster of a fighter, from the comic series I can conclude so much. She was put down by Puss with one hit, literally
. Bad-ass? Yes. Uber strong? Not that much.