Most popular fetish?

Who knows for sure? Feet, footwear (especially high boots), leather,diapers, PVC and latex are all common fetishes. Judging from the questions on this site, various forms of foot fetish are far ahead.

Foot fetishism is one of the most common fetishes.

One fetish that I love is wrestling. I like to wrestle with whomever is my current girlfriend and sometimes they think it is weird but to me it is a form of stimulation without penetration, although sometimes she will get worked up enough and penetration just becomes part of the equation.