Archangel of Thune

Flying
Lifelink (Damage dealt by this creature also causes you to gain that much life.)
Whenever you gain life, put a +1/+1 counter on each creature you control.

Archivist of Oghma

Flash
Whenever an opponent searches their library, you gain 1 life and draw a card.

Ajani's Welcome

Whenever a creature you control enters, you gain 1 life.

Lifegift

Whenever a land enters, you may gain 1 life.

Authority of the Consuls

Creatures your opponents control enter tapped.
Whenever a creature an opponent controls enters, you gain 1 life.