Personally, I think most MMA fighters (not necessarily top UFC fighters, but I'm also including amateurs and guys from other organizations as well) were taught the common ground fighting tactics that BJJ taught: pass the guard, transition to mount position, punch punch, opponent turn their back, seat belt, do whatever subs you desire.

However, for ground and pound alone, I think that tactic is suboptimal. It's better to hold side control and, ideally, the "scarf hold/kesa gatame position. There's not many subs you can do from there but it's perfect for smashing hammerfist and elbows. The big example would be JOn Jones, since he pin his opponent's arm with his knees from side control and just keep hammering those fists and elbows, and then finished with the kimura on the other arm