^ They do work, you just need to know which enemies are immune/resistant
As for other combos I found a simple boulder bash + fireball a crazy AOE damage combo
Also, ice elementals are great to summon right in the enemy's face, as after it dies it leaves a pool of frozen ice tripping enemies who try to advance with hilarious results
Only problem is that after the battle I forget its there and trip over myself!
I was going to suicide because of Hiberheim map. Full of tripping, rolling on the ground.