29. IG-88
One of the galaxy's most feared bounty hunters, IG-88 was an assassin droid who killed his makers immediately upon activation and subsequently downloaded his consciousness into three identical copies. The droids frequently ran afoul of Boba Fett who eventually destroyed three of the four copies. He only appears onscreen for a few seconds in the middle of Empire Strikes Back (he can also be seen in the garbage room of Cloud City) as one of the elite bounty hunters hired to find the Millennium Falcon after the Battle of Hoth. The expanded universe makes IG-88 even more memorable. He has a ship called the IG 2000 which was one of the most powerful vessels of its size in the galaxy. He is a walking arsenal with numerous weapons emplacements all over his body and is easily the most intimidating looking droid in Star Wars. Even though he was constantly outsmarted by Fett, IG-88 was one of his most dangerous foes and it would be really nice to see him appear in the rumored standalone Boba Fett movie.