Not too many heavies that look all that incredible. Overeem, and Lesnar are the two standouts as far as big freaky looking guys. But it ends up being Josh Barnett who was on roids... The thing is, appearance means jack **** in most cases. There are guys who you would never suspect are on roids that are, and guys who you suspect may be on them that would never think about touching them. The only real level you could pretty much guarantee roids are being used are on the top level strong man and powerlifting competitions, and the Mr. Universe Calibre bodybuilders like the ones I mentioned to include all in their league. Otherwise, it's not exactly obvious. You can be too muscled for MMA, at the same time roids can do great things for you, like help you recover from a serious injury in half the time. In the end, it's very complicated, but in general it isn't a given who is on them, and who isn't. Generally, you can't tell just by looks, though I think a case could be made against Overeem.