Life Goes On

You gain 4 life. If a creature died this turn, you gain 8 life instead.

Moldering Karok

Kazandu Nectarpot

Landfall — Whenever a land you control enters, you gain 1 life.

Douse in Gloom

Douse in Gloom deals 2 damage to target creature and you gain 2 life.

Kheru Dreadmaw

Defender
{1}{G}, Sacrifice another creature: You gain life equal to the sacrificed creature's toughness.

Natural End

Destroy target artifact or enchantment. You gain 3 life.

Wolf's Quarry

Create three 1/1 green Boar creature tokens with "When this creature dies, create a Food token." (A Food token is an artifact with "{2}, {T}, Sacrifice this artifact: You gain 3 life.")

Deathless Knight

Haste
When you gain life for the first time each turn, return Deathless Knight from your graveyard to your hand.

Daggerdrome Imp

Flying
Lifelink (Damage dealt by this creature also causes you to gain that much life.)

Severed Strands

As an additional cost to cast this spell, sacrifice a creature.
You gain life equal to the sacrificed creature's toughness. Destroy target creature an opponent controls.

Highland Game

When Highland Game dies, you gain 2 life.

Sylvan Brushstrider

When Sylvan Brushstrider enters, you gain 2 life.

Nirkana Assassin

Whenever you gain life, Nirkana Assassin gains deathtouch until end of turn. (Any amount of damage it deals to a creature is enough to destroy it.)

Boot Nipper

Boot Nipper enters with your choice of a deathtouch counter or a lifelink counter on it.

Voracious Wurm

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

Blood Researcher

Menace (This creature can't be blocked except by two or more creatures.)
Whenever you gain life, put a +1/+1 counter on Blood Researcher.