Serene Steward

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

Arborback Stomper

Trample
When Arborback Stomper enters, you gain 5 life.

Healer of the Pride

Whenever another creature you control enters, you gain 2 life.

Azor, the Lawbringer

Flying
When Azor, the Lawbringer enters, each opponent can't cast instant or sorcery spells during that player's next turn.
Whenever Azor attacks, you may pay {X}{W}{U}{U}. If you do, you gain X life and draw X cards.

Sunspring Expedition

Landfall — Whenever a land enters under your control, you may put a quest counter on Sunspring Expedition.
Remove three quest counters from Sunspring Expedition and sacrifice it: You gain 8 life.

Overrule

Counter target spell unless its controller pays {X}. You gain X life.

Ajani's Mantra

At the beginning of your upkeep, you may gain 1 life.

Will, Scion of Peace

Vigilance
{T}: Spells you cast this turn that are white and/or blue cost {X} less to cast, where X is the amount of life you gained this turn. Activate only as a sorcery.

Accomplished Alchemist

{T}: Add one mana of any color.
{T}: Add X mana of any one color, where X is the amount of life you gained this turn.

Dawn of Hope

Whenever you gain life, you may pay {2}. If you do, draw a card.
{3}{W}: Create a 1/1 white Soldier creature token with lifelink.

Celestial Unicorn

Whenever you gain life, put a +1/+1 counter on Celestial Unicorn.

Voracious Wurm

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

Well of Lost Dreams

Whenever you gain life, you may pay {X}, where X is less than or equal to the amount of life you gained. If you do, draw X cards.

Pledge of Unity

Put a +1/+1 counter on each creature you control. You gain 1 life for each creature you control.

Fall of the Gavel

Nykthos Paragon

Whenever you gain life, you may put that many +1/+1 counters on each creature you control. Do this only once each turn.

Ivory Tower

At the beginning of your upkeep, you gain X life, where X is the number of cards in your hand minus 4.

Shanna, Purifying Blade

Lifelink
At the beginning of your end step, you may pay {X}. If you do, draw X cards. X can't be greater than the amount of life you gained this turn.

Union of the Third Path

Draw a card, then you gain life equal to the number of cards in your hand.

Trelasarra, Moon Dancer

Whenever you gain life, put a +1/+1 counter on Trelasarra, Moon Dancer and scry 1. (Look at the top card of your library. You may put that card on the bottom.)

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.

Sheltering Word

Target creature you control gains hexproof until end of turn. You gain life equal to that creature's toughness. (A creature with hexproof can't be the target of spells or abilities your opponents control.)

Heroes' Reunion

Vigil for the Lost

Whenever a creature you control dies, you may pay {X}. If you do, you gain X life.

Ajani's Pridemate

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

Path of Bravery

As long as your life total is greater than or equal to your starting life total, creatures you control get +1/+1.
Whenever one or more creatures you control attack, you gain life equal to the number of attacking creatures.

Lathiel, the Bounteous Dawn

Lifelink
At the beginning of each end step, if you gained life this turn, distribute up to that many +1/+1 counters among any number of other target creatures.

Marina Vendrell's Grimoire

When Marina Vendrell's Grimoire enters, if you cast it, draw five cards.
You have no maximum hand size and don't lose the game for having 0 or less life.
Whenever you gain life, draw that many cards.
Whenever you lose life, discard that many cards. Then if you have no cards in hand, you lose the game.