Call for Blood

As an additional cost to cast this spell, sacrifice a creature.
Target creature gets -X/-X until end of turn, where X is the sacrificed creature's power.

Sword of the Ages

Sword of the Ages enters tapped.
{T}, Sacrifice Sword of the Ages and any number of creatures you control: Sword of the Ages deals X damage to any target, where X is the total power of the creatures sacrificed this way, then exile Sword of the Ages and those creature cards.

Death Bomb

As an additional cost to cast this spell, sacrifice a creature.
Destroy target nonblack creature. It can't be regenerated. Its controller loses 2 life.

Gate to Phyrexia

Sacrifice a creature: Destroy target artifact. Activate only during your upkeep and only once each turn.

Phyrexian Tribute

As an additional cost to cast this spell, sacrifice two creatures.
Destroy target artifact.