Aetherflux Reservoir

Whenever you cast a spell, you gain 1 life for each spell you've cast this turn.
Pay 50 life: Aetherflux Reservoir deals 50 damage to any target.

Nyx-Fleece Ram

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

Dictate of Heliod

Sunbond

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

Oppressive Rays

Enchant creature
Enchanted creature can't attack or block unless its controller pays {3}.
Activated abilities of enchanted creature cost {3} more to activate.

Ajani, Strength of the Pride

+1: You gain life equal to the number of creatures you control plus the number of planeswalkers you control.
−2: Create a 2/2 white Cat Soldier creature token named Ajani's Pridemate with "Whenever you gain life, put a +1/+1 counter on Ajani's Pridemate."
0: If you have at least 15 life more than your starting life total, exile Ajani, Strength of the Pride and each artifact and creature your opponents control.

Harvestguard Alseids

Constellation — Whenever Harvestguard Alseids or another enchantment you control enters, prevent all damage that would be dealt to target creature this turn.

Radiant Fountain

When Radiant Fountain enters, you gain 2 life.
{T}: Add {C}.

Marked by Honor

Enchant creature
Enchanted creature gets +2/+2 and has vigilance. (Attacking doesn't cause it to tap.)

Mass Calcify

Plains

Sungrace Pegasus

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

Ajani's Pridemate

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

Boonweaver Giant

When Boonweaver Giant enters, you may search your graveyard, hand, and/or library for an Aura card and put it onto the battlefield attached to Boonweaver Giant. If you search your library this way, shuffle.

Spectra Ward

Enchant creature
Enchanted creature gets +2/+2 and has protection from each color. This effect doesn't remove Auras. (It can't be blocked, targeted, or dealt damage by anything that's white, blue, black, red, or green.)

Sphere of Safety

Creatures can't attack you or planeswalkers you control unless their controller pays {X} for each of those creatures, where X is the number of enchantments you control.

Soul's Attendant

Whenever another creature enters, you may gain 1 life.

Staff of the Sun Magus

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

Dawnbringer Charioteers

Flying, lifelink
Heroic — Whenever you cast a spell that targets Dawnbringer Charioteers, put a +1/+1 counter on Dawnbringer Charioteers.

Elixir of Immortality

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