Have

Swift Response

Mesa Unicorn

Lifelink (Damage dealt by this creature also causes you to gain that much life.)

Alabaster Mage

{1}{W}: Target creature you control gains lifelink until end of turn. (Damage dealt by the creature also causes its controller to gain that much life.)

Plains

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.

Anointed Chorister

Lifelink (Damage dealt by this creature also causes you to gain that much life.)
{4}{W}: This creature gets +3/+3 until end of turn.

Light of Promise

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

Thriving Heath

This land enters tapped. As it enters, choose a color other than white.
{T}: Add {W} or one mana of the chosen color.

Basri's Acolyte

Lifelink (Damage dealt by this creature also causes you to gain that much life.)
When this creature enters, put a +1/+1 counter on each of up to two other target creatures you control.

Speaker of the Heavens

Vigilance, lifelink (Attacking doesn't cause this creature to tap. Damage dealt by this creature also causes you to gain that much life.)
{T}: Create a 4/4 white Angel creature token with flying. Activate only if you have at least 7 life more than your starting life total and only as a sorcery.

Doctor

Griffin Aerie

At the beginning of your end step, if you gained 3 or more life this turn, create a 2/2 white Griffin creature token with flying.

Bulwark Giant

When this creature enters, you gain 5 life.

Stone Haven Pilgrim

Whenever this creature attacks, if you control an artifact or enchantment, this creature gets +1/+1 and gains lifelink until end of turn.

Angel of Mercy

Flying
When this creature enters, you gain 3 life.

Revitalize

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.

Rhox Faithmender

Lifelink (Damage dealt by this creature also causes you to gain that much life.)
If you would gain life, you gain twice that much life instead.

Blighted Steppe

{T}: Add {C}.
{3}{W}, {T}, Sacrifice this land: You gain 2 life for each creature you control.

Moment of Heroism

Target creature gets +2/+2 and gains lifelink until end of turn. (Damage dealt by the creature also causes its controller to gain that much life.)

Brightmare

When this creature enters, tap up to one target creature. You gain life equal to that creature's power.

Faith's Fetters

Enchant permanent
When this Aura enters, you gain 4 life.
Enchanted permanent can't attack or block, and its activated abilities can't be activated unless they're mana abilities.

Take Heart

Target creature gets +2/+2 until end of turn. You gain 1 life for each attacking creature you control.

Kabira Crossroads

This land enters tapped.
When this land enters, you gain 2 life.
{T}: Add {W}.