Leveler

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

Echoing Truth

Return target nonland permanent and all other permanents with the same name as that permanent to their owners' hands.

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.

Muldrotha, the Gravetide

During each of your turns, you may play a land and cast a permanent spell of each permanent type from your graveyard. (If a card has multiple permanent types, choose one as you play it.)

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.