Languish

All creatures get -4/-4 until end of turn.

Grazing Gladehart

Landfall — Whenever a land you control enters, you may gain 2 life.

Essence Warden

Whenever another creature enters, you gain 1 life.

Read the Bones

Scry 2, then draw two cards. You lose 2 life.

Ikra Shidiqi, the Usurper

Menace
Whenever a creature you control deals combat damage to a player, you gain life equal to that creature's toughness.
Partner (You can have two commanders if both have partner.)

Filigree Familiar

When Filigree Familiar enters, you gain 2 life.
When Filigree Familiar dies, draw a card.

Voracious Wurm

Voracious Wurm enters with X +1/+1 counters on it, where X is the amount of life you've gained this turn.

Putrefy

Destroy target artifact or creature. It can't be regenerated.

Retreat to Kazandu

Landfall — Whenever a land you control enters, choose one —
• Put a +1/+1 counter on target creature.
• You gain 2 life.

Deathgreeter

Whenever another creature dies, you may gain 1 life.

Murder

Golgari Charm

Choose one —
• All creatures get -1/-1 until end of turn.
• Destroy target enchantment.
• Regenerate each creature you control.

Epicure of Blood

Whenever you gain life, each opponent loses 1 life.

Forest

Defiant Bloodlord

Flying
Whenever you gain life, target opponent loses that much life.

Bloodthirsty Aerialist

Flying
Whenever you gain life, put a +1/+1 counter on Bloodthirsty Aerialist.

Servant of Tymaret

Inspired — Whenever Servant of Tymaret becomes untapped, each opponent loses 1 life. You gain life equal to the life lost this way.
{2}{B}: Regenerate Servant of Tymaret.

Underworld Connections

Enchant land
Enchanted land has "{T}, Pay 1 life: Draw a card."

Ravenous Chupacabra

When Ravenous Chupacabra enters, destroy target creature an opponent controls.

Bloodbond Vampire

Whenever you gain life, put a +1/+1 counter on Bloodbond Vampire.

Falkenrath Noble

Flying
Whenever Falkenrath Noble or another creature dies, target player loses 1 life and you gain 1 life.

Ageless Entity

Whenever you gain life, put that many +1/+1 counters on Ageless Entity.

Swamp

Oathsworn Vampire

Oathsworn Vampire enters tapped.
You may cast Oathsworn Vampire from your graveyard if you gained life this turn.