Shilgengar, Sire of Famine
REALITY SHIFT While blue can struggle to deal with opposing armies, it can do an arguably too good a job at removing single creatures
(Look at the top two cards of your library, then put any number of them into your graveyard and the rest on top of your library in any order.) At the beginning of your end step, you may pay and exile eight cards from your graveyard
We know that the greater the demand for the card, the more expensive it will be, but its not a direct correlation
7: Exile the top seven cards of your library
But if you have a Command Tower, which makes mana depending on your commanders color identity, you have access to all the colors you could possibly need