Brazilian Jiu-Jitsu (commonly called BJJ)
BJJ is founded on the concept that a smaller, weaker person can successfully defend themselves against a bigger, stronger, heavier opponent.
This is done by using technique, leverage, and most notably, taking the fight to the ground, and then applying joint locks and chokeholds to defeat the opponent.
Muay Thai (Thai boxing or Kickboxing)
Muay Thai is a combat sport of Thailand that uses stand-up striking along with various clinching techniques.
This discipline is known as the "art of eight limbs" as it is characterized by the combined use of fists, elbows, knees, and shins.