Doomskar

Destroy all creatures.
Foretell {1}{W}{W} (During your turn, you may pay {2} and exile this card from your hand face down. Cast it on a later turn for its foretell cost.)

Grave Pact

Whenever a creature you control dies, each other player sacrifices a creature of their choice.

Spreading Plague

Whenever a creature enters, destroy all other creatures that share a color with it. They can't be regenerated.

Visara the Dreadful

Flying
{T}: Destroy target creature. It can't be regenerated.

No Mercy

Whenever a creature deals damage to you, destroy it.

Damnation

Destroy all creatures. They can't be regenerated.

End Hostilities

Destroy all creatures and all permanents attached to creatures.

Lethal Vapors

Whenever a creature enters, destroy it.
{0}: Destroy this enchantment. You skip your next turn. Any player may activate this ability.

Call to the Grave

At the beginning of each player's upkeep, that player sacrifices a non-Zombie creature of their choice.
At the beginning of the end step, if no creatures are on the battlefield, sacrifice this enchantment.

Toxic Deluge

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

Day of Judgment

Avatar of Woe

If there are ten or more creature cards total in all graveyards, this spell costs {6} less to cast.
Fear (This creature can't be blocked except by artifact creatures and/or black creatures.)
{T}: Destroy target creature. It can't be regenerated.

Innocent Blood

Each player sacrifices a creature of their choice.

Barter in Blood

Each player sacrifices two creatures of their choice.

Dictate of Erebos

Flash
Whenever a creature you control dies, each opponent sacrifices a creature of their choice.