My favorite, at least right now, is [[haktos the unscarred]]. His rigid RRWW cost makes it so I can't always get him out quickly, but when he comes out it's interesting to see how my opponent's deal with him.

He has to attack every turn, and he doesn't have any fancy abilities like trample or first strike so all the opponent needs is a 1 power creature of the right CMC to block and he's toast. Or any board wipe will take care of him, and most spot removal is either 2, 3, or 4 CMC anyways. But if the opponent can't handle him, they're automatically put on a timer which often changes their game plan.

I've many many different versions of decks around him, both in standard and brawl, and they're all fun.
Some are full of burn and removal to clear his path.
Some are mostly white weenie focused to chip damage where ever possible.
Some are enchantment focused (which is extra humorous when i'm trying to put auras on Haktos but all I have is a [[commanding presence]] but he has protection from 4 CMC.

He's just a fun card to play around with. In my opinion, perfect for brawl because he's just not competitive at all what with the randomness of his ability.