Elas il-Kor, Sadistic Pilgrim

Deathtouch
Whenever another creature you control enters, you gain 1 life.
Whenever another creature you control dies, each opponent loses 1 life.

Sunlit Marsh

({T}: Add {W} or {B}.)
Sunlit Marsh enters tapped.

Midnight Reaper

Whenever a nontoken creature you control dies, this creature deals 1 damage to you and you draw a card.

Doom Blade

Village Rites

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

Gavony Unhallowed

Whenever another creature you control dies, put a +1/+1 counter on Gavony Unhallowed.

Hunted Witness

When Hunted Witness dies, create a 1/1 white Soldier creature token with lifelink.

Doomed Dissenter

When Doomed Dissenter dies, create a 2/2 black Zombie creature token.

Easterling Vanguard

When Easterling Vanguard dies, amass Orcs 1. (Put a +1/+1 counter on an Army you control. It's also an Orc. If you don't control an Army, create a 0/0 black Orc Army creature token first.)

Teysa Karlov

If a creature dying causes a triggered ability of a permanent you control to trigger, that ability triggers an additional time.
Creature tokens you control have vigilance and lifelink.

Denethor, Ruling Steward

At the beginning of your end step, if a creature died under your control this turn, create a 1/1 white Human Soldier creature token.
{2}, Sacrifice another creature: Each opponent loses 1 life and you gain 1 life.

Mortify

Reassembling Skeleton

{1}{B}: Return this card from your graveyard to the battlefield tapped.

Swamp

Scoured Barrens

This land enters tapped.
When this land enters, you gain 1 life.
{T}: Add {W} or {B}.

Aron, Benalia's Ruin

Menace (This creature can't be blocked except by two or more creatures.)
{W}{B}, {T}, Sacrifice another creature: Put a +1/+1 counter on each creature you control.