The Meathook Massacre

When The Meathook Massacre enters, each creature gets -X/-X until end of turn.
Whenever a creature you control dies, each opponent loses 1 life.
Whenever a creature an opponent controls dies, you gain 1 life.

Damnation

Destroy all creatures. They can't be regenerated.

Imperial Seal

Search your library for a card, then shuffle and put that card on top. You lose 2 life.

Diabolic Tutor

Search your library for a card, put that card into your hand, then shuffle.

Necropotence

Skip your draw step.
Whenever you discard a card, exile that card from your graveyard.
Pay 1 life: Exile the top card of your library face down. Put that card into your hand at the beginning of your next end step.

Grim Tutor

Search your library for a card, put that card into your hand, then shuffle. You lose 3 life.

Toxic Deluge

As an additional cost to cast this spell, pay X life.
All creatures get -X/-X until end of turn.

Deadly Rollick

If you control a commander, you may cast this spell without paying its mana cost.
Exile target creature.