Depends on what you consider "performance enhancing."
Banned drugs in the leagues I think are relatively low, at least in terms of taking those drugs above what the permitted amount is for a positive test. But there's so many drugs that are certainly "performance enhancing" that aren't banned, new cocktails and new mixes of drugs. Most NFL and NBA players have independent trainers that basically act as personal drug compounding labs for the players, and mix and match cocktails of substances, and usually most of these trainers avoid adding something that's banned... But every year there's a handful of players that get suspended for PEDs because their personal compounder added too much of something that's on the banned list, or the player too 2 pills when he was supposed to take 1 before getting a drug screening. That's what happened with Will Fuller and Bradley Roby this season in the NFL. They both go to the same trainer ("pharmacist"), the trainer basically acts as a drug compounder and was giving them a regiment throughout the season, who knows if they were over the levels to test positive throughout the season, but at some point they took too much of whatever the trainer was giving them (or he gave them too much), or perhaps they didn't take a masking agent, or any number of other possibilities, and then they tested over the positive limit.
I'm only salty about that because I made an aggressive trade for Will Fuller the week before he was suspended (Dealt Aaron Rodgers for WIll Fuller), Fuller dropped 35pts in that game, looked like a major win for me, and then he tested positive the next day and was done.
