Wrenn and Seven

+1: Reveal the top four cards of your library. Put all land cards revealed this way into your hand and the rest into your graveyard.
0: Put any number of land cards from your hand onto the battlefield tapped.
−3: Create a green Treefolk creature token with reach and "This creature's power and toughness are each equal to the number of lands you control."
−8: Return all permanent cards from your graveyard to your hand. You get an emblem with "You have no maximum hand size."

Sewer Nemesis

As Sewer Nemesis enters, choose a player.
Sewer Nemesis's power and toughness are each equal to the number of cards in the chosen player's graveyard.
Whenever the chosen player casts a spell, that player mills a card.

Lord of the Void

Flying
Whenever Lord of the Void deals combat damage to a player, exile the top seven cards of that player's library, then put a creature card from among them onto the battlefield under your control.

Lord of Extinction

Lord of Extinction's power and toughness are each equal to the number of cards in all graveyards.

Penumbra Wurm

Trample
When Penumbra Wurm dies, create a 6/6 black Wurm creature token with trample.

Lord of the Forsaken

Flying, trample
{B}, Sacrifice another creature: Target player mills three cards.
Pay 1 life: Add {C}. Spend this mana only to cast a spell from your graveyard.

Painful Quandary

Whenever an opponent casts a spell, that player loses 5 life unless they discard a card.

Umbra Stalker

Chroma — Umbra Stalker's power and toughness are each equal to the number of black mana symbols in the mana costs of cards in your graveyard.