fun item in my setting: voidweave armor
basically just, fabric made of tiny strands of void steel, typically rather form-fitting. it's used for its energy absorption and redirection properties.
so for example, a suit of voidweave getting hit by a spell would just absorb the mana out of it, and then the wearer could pull that mana out and use it for a spell of their own - or let the charge build up from many such attacks, and fire it out as a concentrated beam