Any of the in game assets (cards,sps,dec,vouchers). I like the idea of cards the most but I understand cards are hard to make deep prize pools for. More specifically I would love to see a Tier style of tournaments where lower stake is lower prize tournaments but higher stake is higher prize. The best would have like top cut of each tournament would get access to the next tier up (like an entry ticket or something). Or only the top tier of tournaments carry big prizes and all the others have PKM so people can climb up to that level with effort along with purchases at PeakMonsters.