Actually, I need to find a study that showed how a full night's sleep, approx 8hrs, improved a cyclist performance by something in the area of 15-20w or something, over someone who only had about 6-7hrs...I'm paraphrasing, but it was fairly significant.
Furthermore, another study I read showed that using those ice/cooling leg machines/contraptions, also improved recovery and gave significant advantage as well.
So I would consider 1) sleep; 2) Ice/Cold and 3) Well, anything and everything.
Furthermore, just my two cents, I believe there are many substances on the list that have no proven effect whatsoever on performance. Yet, the WADA based off silly beliefs, urban legend and junk science etc..put things on there to make some claim out of stupidity/politics to show they are doing something about actual performance enhancing substances.
An example, why can you take albuterol or allergy medications that allow you to even get on the bike? That is performance enhancing IMO. So your performance goes from basically zero, not being able to ride, to being able to ride/compete. What is the definition and "baseline" for what performance enhancing is? It is all relative and arbitrary performance. Hence why so many substances don't do anything for it on the bike, and many off do depending on your definition on what it means.
So let us first go back and start with what constitutes "Performance Enhacing", and take it from there what makes something actually scientifically enhance performance. I'm guessing this thread will go on forever with that idea.