Most likely there are requests for these but would add to it again. Weightlifting, boxing and gymnastics are some of the most popular sports in the Olympics yet there are no stamps for them. Boxing is also a very popular sport that has spawned some of the greatest athletes like Muhammed Ali, Joe Louis and Manny Pacquiao. In gymnastics there is Nadia Comaneci.
Attaching here samples of boxing, gymnastics and weightlifting stamps.