Gene LeBell was far from the most successful professional wrestler regardless of what metric you use, however in terms of influence in wrestling and in mixed martial arts he is pretty high up the food chain.  LeBell was a legitimate judo star, and he worked with some of the greats including Bruce Lee and Chuck Norris and was a conduit to Hollywood and helped wrestlers get work in some film and tv work.  A decent wrestler who held a few regional titles he would also co-own the NWA Hollywood promotion.

Forgive us as we will use the term "midget" wrestler as that is what they were called back then and that was the name of the titles that they held.

You could argue that Bart Gunn really got the shaft by the WWE and as such you forget that he had a decent run.  He entered the WWE with his kayfabe brother, Billy, and they would win the World Tag Team Championship three times.  When the team broke-up they saw more money in Billy and eventually (albeit in another tag team), he became the much bigger star when he was in the New Age Outlaws and finally D-Generation X.