Monkey Cage

When a creature enters the battlefield, sacrifice Monkey Cage and create X 2/2 green Monkey creature tokens, where X is that creature's mana value.

Endrek Sahr, Master Breeder

Whenever you cast a creature spell, create X 1/1 black Thrull creature tokens, where X is that spell's mana value.
When you control seven or more Thrulls, sacrifice Endrek Sahr, Master Breeder.

Greater Good

Sacrifice a creature: Draw cards equal to the sacrificed creature's power, then discard three cards.

Soldevi Adnate

{T}, Sacrifice a black or artifact creature: Add an amount of {B} equal to the sacrificed creature's mana value.

Ghoulcaller Gisa

{B}, {T}, Sacrifice another creature: Create X 2/2 black Zombie creature tokens, where X is the sacrificed creature's power.

Hogaak, Arisen Necropolis

You can't spend mana to cast this spell.
Convoke, delve (Each creature you tap while casting this spell pays for {1} or one mana of that creature's color. Each card you exile from your graveyard pays for {1}.)
You may cast Hogaak, Arisen Necropolis from your graveyard.
Trample

Morbid Curiosity

As an additional cost to cast this spell, sacrifice an artifact or creature.
Draw cards equal to the mana value of the sacrificed permanent.