I get that the limits of his magic are left deliberately vague, but what have we seen him do with it so far?
He can use it to raise zombies, control people's movements, summon ice/stone spikes, survive lethal wounds, create barriers, make other people unkillable, reverse projectiles launched at him, hear the pasts of the dead, destroy or sever body parts, summoning weapons, and of course illusions.
Did I miss any?