Congregate

Target player gains 2 life for each creature on the battlefield.

Plains

Heliod's Intervention

Choose one —
• Destroy X target artifacts and/or enchantments.
• Target player gains twice X life.

Condemn

Put target attacking creature on the bottom of its owner's library. Its controller gains life equal to its toughness.

Aria of Flame

When Aria of Flame enters, each opponent gains 10 life.
Whenever you cast an instant or sorcery spell, put a verse counter on Aria of Flame, then it deals damage equal to the number of verse counters on it to target player or planeswalker.

False Cure

Until end of turn, whenever a player gains life, that player loses 2 life for each 1 life they gained.

Happily Ever After

When Happily Ever After enters, each player gains 5 life and draws a card.
At the beginning of your upkeep, if there are five colors among permanents you control, there are six or more card types among permanents you control and/or cards in your graveyard, and your life total is greater than or equal to your starting life total, you win the game.

Plague Drone

Flying
Rot Fly — If an opponent would gain life, that player loses that much life instead.

Luminate Primordial

Vigilance
When Luminate Primordial enters, for each opponent, exile up to one target creature that player controls and that player gains life equal to its power.

Swift Justice

Until end of turn, target creature gets +1/+0 and gains first strike and lifelink.

Grotesque Mutation

Target creature gets +3/+1 and gains lifelink until end of turn. (Damage dealt by the creature also causes its controller to gain that much life.)

Alchemist's Gift

Target creature gets +1/+1 and gains your choice of deathtouch or lifelink until end of turn. (Any amount of damage a creature with deathtouch deals to a creature is enough to destroy it. Damage dealt by a creature with lifelink also causes its controller to gain that much life.)

Illumination

Counter target artifact or enchantment spell. Its controller gains life equal to its mana value.

Tainted Remedy

If an opponent would gain life, that player loses that much life instead.

Mortal's Ardor

Target creature gets +1/+1 and gains lifelink until end of turn. (Damage dealt by the creature also causes its controller to gain that much life.)

Swords to Plowshares

Exile target creature. Its controller gains life equal to its power.

Solitude

Flash
Lifelink
When Solitude enters, exile up to one other target creature. That creature's controller gains life equal to its power.
Evoke—Exile a white card from your hand.

Swamp

Toxin Analysis

Target creature gains deathtouch and lifelink until end of turn. Investigate. (Create a Clue token. It's an artifact with "{2}, Sacrifice this artifact: Draw a card.")

Life Burst

Target player gains 4 life, then gains 4 life for each card named Life Burst in each graveyard.

Benevolent Offering

Choose an opponent. You and that player each create three 1/1 white Spirit creature tokens with flying.
Choose an opponent. You gain 2 life for each creature you control and that player gains 2 life for each creature they control.