There is one other term for butt rock. It has nothing to do with a genre of music or era, like all of the above, but actually has to do with music within a movie or video game.
Butt rock is terribly cheesy heavy metal played in a scene or moment to make it more "intense". Hundreds of things have butt rock, usually in action movies and games. The music isn't by any particular artist, but just created by some people. Think of it as Elevator music.
I couldn't stand the butt rock playing when he whipped out that machine gun and shot all those ninjas.