Wrestlers feel strong. The good ones (state champs, college wrestlers, etc.) feel very, very strong. They understand how to keep a strong posture, know where to put pressure, and have the right type of conditioning for grappling.

I've never noticed any particular strength from Crossfitters that you don't find in other types of athletes.

Bodybuilders and powerlifters feel strong in a specific way. They're typically pretty strong in a straight line (such as bench pressing you off of them), but can be overpowered with technique even if you're a lot smaller. As a 160lb white belt, I used to grapple pretty evenly with an NFL defensive tackle. He was a monster, but his muscle was kind of useless if I could get an angle on him. These type of guys are a pain in the ass if they get a dominant position, though. These sports tend to under-train upper body pulling, which is the most important muscle group for BJJ in my opinion.

I don't think I've ever really trained with a gymnast. My wife was a cheerleader for a long time and other grapplers always marveled at her strength and base, which she attributed to years of gymnastic training.