Almost all of Taekwondo’s kicks have been used successfully in the ufc except the acrobatics one and taekwondo has more than just kicks in it arsenal.Hapkido is taught in a lot of taekwondo places in Korea. Hapkido has a lot of the same moves as jujitsu and some style of hapkido cover ground fighting.
http://youtube.com/watch?v=xA737gJa8Yg