Oh thank goodness someone else likes caveman slam. You should check out Snuffed On Sight. It's goofy even by the standards of its kind.In post 9, Doctor Drew wrote: My two completely different go to's are underground European techno, really atmospheric and and almost dark and eerie sounding. Coupled with the the repetitive 4 on the Floor beat really keeps me in an almost trance like state that makes the workout fly by.
The other is Brutal Slamming Death Metal. Lyrics that you can barely tell are lyrics(which is good because the subject matter if the songs can get a little out there), and a back an forth between blast beats and hyper riffing with super slowed down beat down like slamming riffs. Definitely knuckle dragger music but damn sure gets you pumped.
My contribution to the topic: have you considered nu metal? No, seriously. Pull up Coal Chamber's Dark Days. Rowboat is a probable skip, but otherwise...