Caffeine is performance enhancing for cycling.
It is also performance enhancing for finance and law. So is adderal.
Physically steroids could help but agree with Steve on painkillers. Plus players can have surgeries that allow them to player longer and better than before. Legal drugs and supplements can have similar effects to the ones that are banned.
I used to lift and Argenine and creatine were big boosts. Nothing illegal but a definite aid. A PED.