I really like engineered explosives. It has a lot of play to it and requires careful play to get the most out of it. You do need a mana base that supports it - I have vivids and tri lands. There's also other cool artifact synergy too. Eg.
I also ring disk. I like that it gives your opponent the opportunity to remove it, so let's done counterplay. I don't have many planeswalkers so it's more difficult to abuse that way.