Augury Adept

Whenever Augury Adept deals combat damage to a player, reveal the top card of your library and put that card into your hand. You gain life equal to its mana value.

Kor Firewalker

Protection from red
Whenever a player casts a red spell, you may gain 1 life.

Serra Ascendant

Lifelink (Damage dealt by this creature also causes you to gain that much life.)
As long as you have 30 or more life, Serra Ascendant gets +5/+5 and has flying.

Conclave Tribunal

Convoke (Your creatures can help cast this spell. Each creature you tap while casting this spell pays for {1} or one mana of that creature's color.)
When Conclave Tribunal enters, exile target nonland permanent an opponent controls until Conclave Tribunal leaves the battlefield.

Soul Warden

Whenever another creature enters, you gain 1 life.

Martyr of Sands

{1}, Reveal X white cards from your hand, Sacrifice Martyr of Sands: You gain three times X life.

Plains

Charmed Stray

Lifelink
When Charmed Stray enters, put a +1/+1 counter on each other creature you control named Charmed Stray.

Spectral Procession

Create three 1/1 white Spirit creature tokens with flying.

Ajani's Pridemate

Whenever you gain life, put a +1/+1 counter on this creature.