Sacrifice a creature: Add {C}{C}.

You may choose not to untap Helm of Possession during your untap step. {2}, {T}, Sacrifice a creature: Gain control of target creature for as long as you control Helm of Possession and Helm of Possession remains tapped.

Sacrifice a creature: Add one mana of any color.

Whenever you sacrifice a permanent, put a +1/+1 counter on Blood Aspirant. {1}{R}, {T}, Sacrifice a creature or enchantment: Blood Aspirant deals 1 damage to target creature. That creature can't block this turn.

When Chittering Witch enters the battlefield, create a number of 1/1 black Rat creature tokens equal to the number of opponents you have. {1}{B}, Sacrifice a creature: Target creature gets -2/-2 until end of turn.

{2}{B}, Sacrifice a creature: Target opponent reveals their hand. You choose a card from it. That player discards that card. Activate only as a sorcery.

Flying, lifelink, hexproof from planeswalkers Boast — {1}{B}, Sacrifice a creature: Each opponent sacrifices a creature or planeswalker. (Activate only if this creature attacked this turn and only once each turn.)

{T}, Sacrifice a creature: Put two +1/+1 counters on target creature. {T}, Remove a counter from a creature you control: Create a Treasure token. {T}, Sacrifice an artifact: Create a 2/1 white and black Inkling creature token with flying. {3}{B}: Untap Fain, the Broker.

{T}, Sacrifice a creature: Return target creature card from your graveyard to the battlefield. Activate only during your upkeep.

Menace Whenever you sacrifice a creature, you may pay {U/B}. If you do, draw a card. ({U/B} can be paid with either {U} or {B}.) {1}, Sacrifice a creature: Kels, Fight Fixer gains indestructible until end of turn.

{2}, Sacrifice a creature: Lyzolda, the Blood Witch deals 2 damage to any target if the sacrificed creature was red. Draw a card if the sacrificed creature was black.

{T}, Sacrifice Phyrexian Plaguelord: Target creature gets -4/-4 until end of turn. Sacrifice a creature: Target creature gets -1/-1 until end of turn.

{T}, Sacrifice two other creatures: Any number of target players each lose 2 life and sacrifice a creature. You add {B}{B} and draw a card.

Flying Whenever you sacrifice a creature, target opponent sacrifices a creature.

{2}{B}, Sacrifice a creature: Create two Treasure tokens. (They're artifacts with "{T}, Sacrifice this artifact: Add one mana of any color.") Sacrifice three Treasures: Draw a card.