Butcher of Malakir

Flying
Whenever Butcher of Malakir or another creature you control dies, each opponent sacrifices a creature of their choice.

Absolute Grace

All creatures have protection from black.

Phyrexian Altar

Sacrifice a creature: Add one mana of any color.

Grave Pact

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

Crown of Awe

Enchant creature
Enchanted creature has protection from black and from red.
Sacrifice Crown of Awe: Enchanted creature and other creatures that share a creature type with it gain protection from black and from red until end of turn.

Altar of Dementia

Sacrifice a creature: Target player mills cards equal to the sacrificed creature's power.

Teysa, Orzhov Scion

Sacrifice three white creatures: Exile target creature.
Whenever another black creature you control dies, create a 1/1 white Spirit creature token with flying.

Altar of the Brood

Whenever another permanent you control enters, each opponent mills a card.

Elenda, the Dusk Rose

Lifelink
Whenever another creature dies, put a +1/+1 counter on Elenda, the Dusk Rose.
When Elenda dies, create X 1/1 white Vampire creature tokens with lifelink, where X is Elenda's power.

Dictate of Erebos

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

Martyr's Cause

Sacrifice a creature: The next time a source of your choice would deal damage to any target this turn, prevent that damage.

Darkest Hour

Cathars' Crusade

Whenever a creature you control enters, put a +1/+1 counter on each creature you control.

Martyr's Bond

Whenever Martyr's Bond or another nonland permanent you control is put into a graveyard from the battlefield, each opponent sacrifices a permanent of their choice that shares a card type with it.