Orim's Prayer

Whenever one or more creatures attack you, you gain 1 life for each attacking creature.

Cleric Class

(Gain the next level as a sorcery to add its ability.)
If you would gain life, you gain that much life plus 1 instead.
{3}{W}: Level 2
Whenever you gain life, put a +1/+1 counter on target creature you control.
{4}{W}: Level 3
When this Class becomes level 3, return target creature card from your graveyard to the battlefield. You gain life equal to that creature's toughness.

The Archimandrite

At the beginning of your upkeep, you gain X life, where X is the number of cards in your hand minus 4.
Whenever you gain life, each Advisor, Artificer, and Monk you control gains vigilance and gets +X/+0 until end of turn, where X is the amount of life you gained.
Tap three untapped Advisors, Artificers, and/or Monks you control: Draw a card.

Angelic Chorus

Whenever a creature you control enters, you gain life equal to its toughness.

Searing Meditation

Whenever you gain life, you may pay {2}. If you do, this enchantment deals 2 damage to any target.

Cradle of Vitality

Whenever you gain life, you may pay {1}{W}. If you do, put a +1/+1 counter on target creature for each 1 life you gained.