Liliana's Steward

{T}, Sacrifice Liliana's Steward: Target opponent discards a card. Activate only as a sorcery.

Gurmag Angler

Delve (Each card you exile from your graveyard while casting this spell pays for {1}.)

Whenever a player sacrifices a creature, you may put a +1/+1 counter on Mortician Beetle.

Sacrifice Death Cultist: Target player loses 1 life and you gain 1 life.

As an additional cost to cast this spell, sacrifice a creature.
Draw two cards.

Target creature gets -1/-1 until end of turn for each Swamp you control.

This spell costs {3} less to cast if a creature died this turn.
Flying, deathtouch

Sacrifice Fume Spitter: Put a -1/-1 counter on target creature.

Target creature gets -1/-1 until end of turn.
Morbid — That creature gets -13/-13 until end of turn instead if a creature died this turn.