I want to say skateboarders but I think that the more famous ones get a pretty fat paycheck. But seriously, slamming off huge stairs and rails probably deserves a lot more. But they get paid to do what they love so its whatever. Hahaha

Table Tennis players are the most underpaid athelete. We work so hard to be able to hakkui the ball and we get no bling bling

Gymnastics is an amateur sport. They mostly don't get paid at all. The very top level ones usually get a bit of funding from their national sports association but it is not much. They mostly still live with their parents.

Hockey players are the most under paid athlete's in all of sports

None really. Mostly they get paid by sponsors and the better you are the better your sponsor.