Honestly 1 strike KO's usually aren't my favorite. It's just over too quickly and suddenly. I prefer sustained violence. I also love combinations, not so much 1 punch KO's. Like a pride Shogun/Wandy. So to me it'd be like RDA, Lineker, Cerrone is up there now that he can throw hands. Wonderboy because his movement etc.
Don't get me wrong I love watching Rumble fight, and I really enjoy that " a KO can happen at any time within the first 2 rounds " kinda deal. But I prefer the sustained violence type fighters. I like fights going longer than 1-2 minutes.
Come to think of it watching Rumble is a lot like watching Conor. Very similar fighters.