The bar fight in Serenity... tiny little girl realistically kicks the $hit out of a room full of people.
Good one.
Add to that the bar fight in Crouching Tiger, Hidden Dragon.
I would also add the end fight of the movie Serenity where Summer Glau takes on the Reavers.
Others that come to mind, the Warriors vs. the Baseball Furies in the Warriors movie. Perhaps that’s because as a Red Sox fan I liked watching Yankees fans get beat up, ha ha ha. And Ajax was always one of my favorite Greek heros, as far as I’m concerned the first Objectivist.
For comedy, the end fight scene from Slap Shot.