Main 3 would have to be : Shielded psions: (anyone who has done 28 difficulty strikes or missions will know how painful these are.) Hobgoblins: not so much alone. But in duos or trios on a harder difficulty these bad boys can pull any guardian down. Phalanx's: note this is only when angry is on so they have no flinch. They can be a pain to drop when you can't knock back.