Forest

Savra, Queen of the Golgari

Whenever you sacrifice a black creature, you may pay 2 life. If you do, each other player sacrifices a creature of their choice.
Whenever you sacrifice a green creature, you may gain 2 life.

Victimize

Choose two target creature cards in your graveyard. Sacrifice a creature. If you do, return the chosen cards to the battlefield tapped.

Accursed Marauder

When Accursed Marauder enters, each player sacrifices a nontoken creature of their choice.

Swamp

Abyssal Gatekeeper

When Abyssal Gatekeeper dies, each player sacrifices a creature of their choice.

Basal Thrull

Skullclamp

Equipped creature gets +1/-1.
Whenever equipped creature dies, draw two cards.
Equip {1}

Blood Artist

Whenever Blood Artist or another creature dies, target player loses 1 life and you gain 1 life.

Arcane Signet

{T}: Add one mana of any color in your commander's color identity.

Ashnod's Altar

Eternal Witness

When Eternal Witness enters, you may return target card from your graveyard to your hand.

Attrition

{B}, Sacrifice a creature: Destroy target nonblack creature.

Animate Dead

Enchant creature card in a graveyard
When Animate Dead enters, if it's on the battlefield, it loses "enchant creature card in a graveyard" and gains "enchant creature put onto the battlefield with Animate Dead." Return enchanted creature card to the battlefield under your control and attach Animate Dead to it. When Animate Dead leaves the battlefield, that creature's controller sacrifices it.
Enchanted creature gets -1/-0.

Zulaport Cutthroat

Whenever Zulaport Cutthroat or another creature you control dies, each opponent loses 1 life and you gain 1 life.

Beledros Witherbloom

Flying
At the beginning of each upkeep, create a 1/1 black and green Pest creature token with "When this creature dies, you gain 1 life."
Pay 10 life: Untap all lands you control. Activate only once each turn.