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.

Mindcrank

Whenever an opponent loses life, that player mills that many cards. (Damage causes loss of life.)

Dawnhart Geist

Whenever you cast an enchantment spell, you gain 2 life.

Boon Reflection

If you would gain life, you gain twice that much life instead.

Grim Feast

At the beginning of your upkeep, Grim Feast deals 1 damage to you.
Whenever a creature is put into an opponent's graveyard from the battlefield, you gain life equal to its toughness.

Soul's Attendant

Whenever another creature enters, you may gain 1 life.

Kraken's Eye

Whenever a player casts a blue spell, you may gain 1 life.

Blood Artist

Whenever Blood Artist or another creature dies, target player loses 1 life and you gain 1 life.

Lifegift

Whenever a land enters, you may gain 1 life.

Golem's Heart

Whenever a player casts an artifact spell, you may gain 1 life.

Curse of Clinging Webs

Enchant player
Whenever a nontoken creature enchanted player controls dies, exile it and you create a 1/2 green Spider creature token with reach.

Demon's Horn

Whenever a player casts a black spell, you may gain 1 life.

Cruel Celebrant

Whenever Cruel Celebrant or another creature or planeswalker you control dies, each opponent loses 1 life and you gain 1 life.

Arcane Signet

{T}: Add one mana of any color in your commander's color identity.

Swamp

Wooden Sphere

Whenever a player casts a green spell, you may pay {1}. If you do, you gain 1 life.

Measure of Wickedness

At the beginning of your end step, sacrifice Measure of Wickedness and you lose 8 life.
Whenever another card is put into your graveyard from anywhere, target opponent gains control of Measure of Wickedness.

Honden of Cleansing Fire

At the beginning of your upkeep, you gain 2 life for each Shrine you control.

Curse of Vitality

Enchant player
Whenever enchanted player is attacked, you gain 2 life. Each opponent attacking that player does the same.

Bilbo, Birthday Celebrant

If you would gain life, you gain that much life plus 1 instead.
{2}{W}{B}{G}, {T}, Exile Bilbo, Birthday Celebrant: Search your library for any number of creature cards, put them onto the battlefield, then shuffle. Activate only if you have 111 or more life.

Sanctum of Stone Fangs

At the beginning of your first main phase, each opponent loses X life and you gain X life, where X is the number of Shrines you control.

Courser of Kruphix

Play with the top card of your library revealed.
You may play lands from the top of your library.
Landfall — Whenever a land you control enters, you gain 1 life.

Bloodchief Ascension

At the beginning of each end step, if an opponent lost 2 or more life this turn, you may put a quest counter on Bloodchief Ascension. (Damage causes loss of life.)
Whenever a card is put into an opponent's graveyard from anywhere, if Bloodchief Ascension has three or more quest counters on it, you may have that player lose 2 life. If you do, you gain 2 life.

Wurm's Tooth

Whenever a player casts a green spell, you may gain 1 life.

Plains

Creeping Bloodsucker

At the beginning of your upkeep, Creeping Bloodsucker deals 1 damage to each opponent. You gain life equal to the damage dealt this way.

Glowing One

Deathtouch
Whenever Glowing One deals combat damage to a player, they get four rad counters.
Whenever a player mills a nonland card, you gain 1 life.

Bastion of Remembrance

When Bastion of Remembrance enters, create a 1/1 white Human Soldier creature token.
Whenever a creature you control dies, each opponent loses 1 life and you gain 1 life.

Light of Promise

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

Golgari Cluestone

{T}: Add {B} or {G}.
{B}{G}, {T}, Sacrifice Golgari Cluestone: Draw a card.

Curse of Fool's Wisdom

Enchant player
Whenever enchanted player draws a card, they lose 2 life and you gain 2 life.
Madness {3}{B} (If you discard this card, discard it into exile. When you do, cast it for its madness cost or put it into your graveyard.)

Essence Warden

Whenever another creature enters, you gain 1 life.

Enduring Tenacity

Whenever you gain life, target opponent loses that much life.
When Enduring Tenacity dies, if it was a creature, return it to the battlefield under its owner's control. It's an enchantment. (It's not a creature.)

Rug of Smothering

Flying
Whenever a player casts a spell, they lose 1 life for each spell they've cast this turn.

Dragon's Claw

Whenever a player casts a red spell, you may gain 1 life.

Sol Ring

Herald of the Pantheon

Enchantment spells you cast cost {1} less to cast.
Whenever you cast an enchantment spell, you gain 1 life.

Gourmand's Talent

(Gain the next level as a sorcery to add its ability.)
During your turn, artifacts you control are Foods in addition to their other types and have "{2}, {T}, Sacrifice this artifact: You gain 3 life."
{2}{G}: Level 2
Whenever you gain life for the first time each turn, create a 3/3 green Raccoon creature token.
{3}{G}: Level 3
Whenever you gain life for the first time each turn, put a +1/+1 counter on each creature you control.

Soul Warden

Elixir of Immortality

{2}, {T}: You gain 5 life. Shuffle Elixir of Immortality and your graveyard into their owner's library.

Paradise Plume

As Paradise Plume enters, choose a color.
Whenever a player casts a spell of the chosen color, you may gain 1 life.
{T}: Add one mana of the chosen color.

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.

Trespasser's Curse

Enchant player
Whenever a creature enchanted player controls enters, that player loses 1 life and you gain 1 life.

Forest

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.

Explore

You may play an additional land this turn.
Draw a card.

Fountain of Renewal

At the beginning of your upkeep, you gain 1 life.
{3}, Sacrifice Fountain of Renewal: Draw a card.