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.

Priest of Ancient Lore

When Priest of Ancient Lore enters, you gain 1 life and draw a card.

Cathedral Sanctifier

When Cathedral Sanctifier enters, you gain 3 life.

Soul Warden

Whenever another creature enters, you gain 1 life.

Heron of Hope

Flying
If you would gain life, you gain that much life plus 1 instead.
{1}{W}: Heron of Hope gains lifelink until end of turn.

Knight of Dawn's Light

First strike
If you would gain life, you gain that much life plus 1 instead.
{1}{W}: Knight of Dawn's Light gets +1/+1 until end of turn.

Suture Priest

Whenever another creature you control enters, you may gain 1 life.
Whenever a creature an opponent controls enters, you may have that player lose 1 life.

Kor Celebrant

Whenever Kor Celebrant or another creature you control enters, you gain 1 life.

Inspiring Overseer

Flying
When this creature enters, you gain 1 life and draw a card.

Luminous Phantom

Flying
Whenever another creature you control leaves the battlefield, you gain 1 life.
If Luminous Phantom would be put into a graveyard from anywhere, exile it instead.

Lunarch Veteran

Whenever another creature you control enters, you gain 1 life.
Disturb {1}{W} (You may cast this card from your graveyard transformed for its disturb cost.)

Lunarch Veteran // Luminous Phantom

Revitalize

Light of Promise

Enchant creature
Enchanted creature has "Whenever you gain life, put that many +1/+1 counters on this creature."

Soul's Attendant

Whenever another creature enters, you may gain 1 life.

Ajani's Pridemate

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

Sunbond

Lone Missionary

When Lone Missionary enters, you gain 4 life.

Celestial Unicorn

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

Ajani's Welcome

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

Gideon's Company

Whenever you gain life, put two +1/+1 counters on Gideon's Company.
{3}{W}: Put a loyalty counter on target Gideon planeswalker.