Lethwei vs Muay Thai – Lethwei includes all the strikes of Muay Thai as well as the use of headbutts. Plus Lethwei fighters generally will only wrap their hands with gauze or fight with bare knuckles.
Catch wrestling is a form of wrestling that involves pinning as well submissions such as neck cranks, twisting armlocks, and toe holds (but does not include chokes).
To choose a martial art you should first take a look at your own goals, atheltic level, and training preference then consider which martial arts are most practical, effective, and available in your area.
Some good options are Brazilian jiu jitsu, boxing, muay thai, wrestling, and mma.
Jiu jitsu is grappling and ground fighting only wherease taekwondo is striking only. BJJ has the advantage in a self defense situation, but the the strikes of TKD are still extremely effective.
Jiu jitsu focuses on submissions through joint locks and strangulation whereas wrestling focuses on securing the take down and pinning your opponent to win the match. Both are very effective grappling based martial arts.