(Note: I don't speak Korean much and so some of the information here may be misinformed or have incorrect spelling)
Derogatory:
babo = stupid
Pyongshin = fool/retard
Kourtong = idiot, clown (not too offensive)
shipsekki/keesekki = cry baby

Exclamation:
Shiba = fuck
Jotkatta / Jottetta = my testicles vanished/were removed

Threatening:
Chugule? = wanna die?
Mogule? = wanna get beaten up?

Inpolite:
Takcho! = Shut up!
Learned most of these in high school.