Leveler

When Leveler enters the battlefield, exile all cards from your library.

Sidisi, Brood Tyrant

Whenever Sidisi, Brood Tyrant enters the battlefield or attacks, mill three cards.
Whenever one or more creature cards are put into your graveyard from your library, create a 2/2 black Zombie creature token.

Doomsday

Search your library and graveyard for five cards and exile the rest. Put the chosen cards on top of your library in any order. You lose half your life, rounded up.

Inverter of Truth

Devoid (This card has no color.)
Flying
When Inverter of Truth enters the battlefield, exile all cards from your library face down, then shuffle all cards from your graveyard into your library.