Retreat to Kazandu

Landfall — Whenever a land you control enters, choose one —
• Put a +1/+1 counter on target creature.
• You gain 2 life.

Laid to Rest

Whenever a Human you control dies, draw a card.
Whenever a creature you control with a +1/+1 counter on it dies, you gain 2 life.

Cloudblazer

Flying
When this creature enters, you gain 2 life and draw two cards.

Sanguine Bond

Whenever you gain life, target opponent loses that much life.

Maja, Bretagard Protector

Other creatures you control get +1/+1.
Landfall — Whenever a land you control enters, create a 1/1 white Human Warrior creature token.

Shattered Angel

Flying
Whenever a land an opponent controls enters, you may gain 3 life.

Knights of the Black Rose

When Knights of the Black Rose enters, you become the monarch.
Whenever an opponent becomes the monarch, if you were the monarch as the turn began, that player loses 2 life and you gain 2 life.

Moldervine Reclamation

Whenever a creature you control dies, you gain 1 life and draw a card.

Scion of the Swarm

Flying
Whenever you gain life, put a +1/+1 counter on Scion of the Swarm.

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.)

Soul's Attendant

Whenever another creature enters, you may gain 1 life.

Faithful Mending

You gain 2 life, draw two cards, then discard two cards.
Flashback {1}{W}{U} (You may cast this card from your graveyard for its flashback cost. Then exile it.)

Heartwarming Redemption

Discard all the cards in your hand, then draw that many cards plus one. You gain life equal to the number of cards in your hand.

Vampiric Link

Enchant creature
Whenever enchanted creature deals damage, you gain that much life.

Bontu's Monument

Black creature spells you cast cost {1} less to cast.
Whenever you cast a creature spell, each opponent loses 1 life and you gain 1 life.

Path to Exile

Exile target creature. Its controller may search their library for a basic land card, put that card onto the battlefield tapped, then shuffle.

Pledge of Unity

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

Soul Warden

Whenever another creature enters, you gain 1 life.

Bloodbond Vampire

Whenever you gain life, put a +1/+1 counter on Bloodbond Vampire.

Markov Purifier

Lifelink
At the beginning of your end step, if you gained life this turn, you may pay {2}. If you do, draw a card.

Elite Guardmage

Flying
When Elite Guardmage enters, you gain 3 life and draw a card.

Bloodthirsty Aerialist

Flying
Whenever you gain life, put a +1/+1 counter on Bloodthirsty Aerialist.

Malakir Familiar

Flying, deathtouch
Whenever you gain life, Malakir Familiar gets +1/+1 until end of turn.

Prosperous Innkeeper

When Prosperous Innkeeper enters, create a Treasure token. (It's an artifact with "{T}, Sacrifice this artifact: Add one mana of any color.")
Whenever another creature you control enters, you gain 1 life.

Essence Warden

Exsanguinate

Each opponent loses X life. You gain life equal to the life lost this way.

Social Climber

Alliance — Whenever another creature you control enters, you gain 1 life.

Reckoner's Bargain

As an additional cost to cast this spell, sacrifice an artifact or creature.
You gain life equal to the sacrificed permanent's mana value. Draw two cards.

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.

Tatyova, Benthic Druid

Landfall — Whenever a land you control enters, you gain 1 life and draw a card.

Dovin's Acuity

When Dovin's Acuity enters, you gain 2 life and draw a card.
Whenever you cast an instant spell during your main phase, you may return Dovin's Acuity to its owner's hand.

Attended Healer

Whenever you gain life for the first time each turn, create a 1/1 white Cat creature token.
{2}{W}: Another target Cleric gains lifelink until end of turn.

Sunbond

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

Kardur, Doomscourge

When Kardur, Doomscourge enters, until your next turn, creatures your opponents control attack each combat if able and attack a player other than you if able.
Whenever an attacking creature dies, each opponent loses 1 life and you gain 1 life.

Spiritualize

Until end of turn, whenever target creature deals damage, you gain that much life.
Draw a card.

Druid Class

(Gain the next level as a sorcery to add its ability.)
Landfall — Whenever a land you control enters, you gain 1 life.
{2}{G}: Level 2
You may play an additional land on each of your turns.
{4}{G}: Level 3
When this Class becomes level 3, target land you control becomes a creature with haste and "This creature's power and toughness are each equal to the number of lands you control." It's still a land.

Revenge of Ravens

Whenever a creature attacks you or a planeswalker you control, that creature's controller loses 1 life and you gain 1 life.

Brainstorm

Draw three cards, then put two cards from your hand on top of your library in any order.

Pulse of Murasa

Return target creature or land card from a graveyard to its owner's hand. You gain 6 life.

Ajani's Pridemate

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

Sphinx's Insight

Draw two cards.
Addendum — If you cast this spell during your main phase, you gain 2 life.

Vizkopa Guildmage

{1}{W}{B}: Target creature gains lifelink until end of turn.
{1}{W}{B}: Whenever you gain life this turn, each opponent loses that much life.

Righteous Cause

Whenever a creature attacks, you gain 1 life.

Twinblade Paladin

Whenever you gain life, put a +1/+1 counter on this creature.
As long as you have 25 or more life, this creature has double strike. (It deals both first-strike and regular combat damage.)

Elas il-Kor, Sadistic Pilgrim

Deathtouch
Whenever another creature you control enters, you gain 1 life.
Whenever another creature you control dies, each opponent loses 1 life.

Light of Promise

Gates of Istfell

Gates of Istfell enters tapped.
{T}: Add {W}.
{2}{W}{U}{U}, {T}, Sacrifice Gates of Istfell: You gain 2 life and draw two cards.

Light of Hope

Choose one —
• You gain 4 life.
• Destroy target enchantment.
• Put a +1/+1 counter on target creature.

Kenrith, the Returned King

{R}: All creatures gain trample and haste until end of turn.
{1}{G}: Put a +1/+1 counter on target creature.
{2}{W}: Target player gains 5 life.
{3}{U}: Target player draws a card.
{4}{B}: Put target creature card from a graveyard onto the battlefield under its owner's control.

Consume

Target player sacrifices a creature with the greatest power among creatures they control. You gain life equal to its power.

Consecrate

Exile target card from a graveyard.
Draw a card.

Consecrate // Consume

Thrilling Discovery

You gain 2 life. Then you may discard two cards. If you do, draw three cards.

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.