The more mana you spend on it, the more dice you need to have at your disposal
I can name two, and its only because I was looking up where Knowledge Exploitation is played (Thada Adel, Acquisitor is just mean)
Varina, Lich Queen [Best Aggressive Card Filtering and Token Burst] Varina, Lich Queen rewards attacking with Zombies by turning combat into card selection, lifegain, and graveyard setup all at once
Ian Malcolm, Chaotician sees Jeff Goldblums beloved scientist forcing players to exile the top card of their library whenever they draw a second card on their turn, before allowing the controlling player to cast spells from any exiled cards using any mana type
And in case you dont want to use Crobat anymore, it wont be locked so that you can trade it for packs or other cards in the future
Read on about the Pokmon Championship Series