Staff of the Sun Magus

Whenever you cast a white spell or a Plains you control enters, you gain 1 life.

Plains

Ajani's Pridemate

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

Kinsbaile Skirmisher

When Kinsbaile Skirmisher enters, target creature gets +1/+1 until end of turn.

Child of Night

Solemn Offering

Destroy target artifact or enchantment. You gain 4 life.

Insatiable Harpy

Sign in Blood

Target player draws two cards and loses 2 life.

Eternal Thirst

Enchant creature
Enchanted creature has lifelink and "Whenever a creature an opponent controls dies, put a +1/+1 counter on this creature." (Damage dealt by a creature with lifelink also causes its controller to gain that much life.)

Staff of the Death Magus

Whenever you cast a black spell or a Swamp you control enters, you gain 1 life.

Shadowcloak Vampire

Pay 2 life: Shadowcloak Vampire gains flying until end of turn. (It can't be blocked except by creatures with flying or reach.)

Sentry of the Underworld

Flying, vigilance
{W}{B}, Pay 3 life: Regenerate Sentry of the Underworld.

Nyx-Fleece Ram

At the beginning of your upkeep, you gain 1 life.

Accursed Spirit

Intimidate (This creature can't be blocked except by artifact creatures and/or creatures that share a color with it.)

Pillar of Light

Exile target creature with toughness 4 or greater.

Mass Calcify

Ulcerate

Target creature gets -3/-3 until end of turn. You lose 3 life.

Soulmender

Tireless Missionaries

When Tireless Missionaries enters, you gain 3 life.

Sungrace Pegasus

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

Wall of Essence

Defender (This creature can't attack.)
Whenever Wall of Essence is dealt combat damage, you gain that much life.

Evolving Wilds

{T}, Sacrifice this land: Search your library for a basic land card, put it onto the battlefield tapped, then shuffle.

Wall of Limbs

Defender (This creature can't attack.)
Whenever you gain life, put a +1/+1 counter on Wall of Limbs.
{5}{B}{B}, Sacrifice Wall of Limbs: Target player loses X life, where X is Wall of Limbs's power.

Witch's Familiar

First Response

At the beginning of each upkeep, if you lost life last turn, create a 1/1 white Soldier creature token.

Swamp

Geist of the Moors

Resolute Archangel

Flying
When Resolute Archangel enters, if your life total is less than your starting life total, it becomes equal to your starting life total.

Blood Host

{1}{B}, Sacrifice another creature: Put a +1/+1 counter on Blood Host and you gain 2 life.

Crippling Blight

Enchant creature
Enchanted creature gets -1/-1 and can't block.

Divine Favor

Enchant creature
When Divine Favor enters, you gain 3 life.
Enchanted creature gets +1/+3.