My last deck was an all-black discard deck.
I lost it when I moved, but it functioned by forcing the opponent to discard his entire hand as soon as possible so that he would have no options to counter me, and then forcing him to draw and discard additional cards - while dealing damage each time he did so. It was very effective.
megrim decks! i found my megrim deck the other night. i remember it not working very well.