Walking Ballista

Walking Ballista enters with X +1/+1 counters on it.
{4}: Put a +1/+1 counter on Walking Ballista.
Remove a +1/+1 counter from Walking Ballista: It deals 1 damage to any target.

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.

Sol Ring

Celestine, the Living Saint

Flying, lifelink
Healing Tears — At the beginning of your end step, return target creature card with mana value X or less from your graveyard to the battlefield, where X is the amount of life you gained this turn.

Howling Mine

At the beginning of each player's draw step, if Howling Mine is untapped, that player draws an additional card.

Loxodon Warhammer

Equipped creature gets +3/+0 and has trample and lifelink.
Equip {3}

Lotus Petal

{T}, Sacrifice Lotus Petal: Add one mana of any color.

Keening Stone

{5}, {T}: Target player mills X cards, where X is the number of cards in that player's graveyard.

Well of Lost Dreams

Whenever you gain life, you may pay {X}, where X is less than or equal to the amount of life you gained. If you do, draw X cards.

Millstone

Soul Warden

Whenever another creature enters, you gain 1 life.

Radiant Fountain

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

Eternity Vessel

Eternity Vessel enters with X charge counters on it, where X is your life total.
Landfall — Whenever a land you control enters, you may have your life total become the number of charge counters on Eternity Vessel.

Heliod, Sun-Crowned

Indestructible
As long as your devotion to white is less than five, Heliod isn't a creature.
Whenever you gain life, put a +1/+1 counter on target creature or enchantment you control.
{1}{W}: Another target creature gains lifelink until end of turn.

Angelic Chorus

Whenever a creature you control enters, you gain life equal to its toughness.

Emeria Shepherd

Flying
Landfall — Whenever a land you control enters, you may return target nonland permanent card from your graveyard to your hand. If that land is a Plains, you may return that nonland permanent card to the battlefield instead.

Gilded Lotus

Oloro, Ageless Ascetic

At the beginning of your upkeep, you gain 2 life.
Whenever you gain life, you may pay {1}. If you do, draw a card and each opponent loses 1 life.
At the beginning of your upkeep, if Oloro, Ageless Ascetic is in the command zone, you gain 2 life.

Chromatic Lantern

Lands you control have "{T}: Add one mana of any color."
{T}: Add one mana of any color.

Fountain of Renewal

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