Soul's Attendant

Whenever another creature enters, you may gain 1 life.

Demonic Tutor

Search your library for a card, put that card into your hand, then shuffle.

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.

Swamp

Plains

Exquisite Blood

Whenever an opponent loses life, you gain that much life.

Vampiric Tutor

Search your library for a card, then shuffle and put that card on top. You lose 2 life.

Famished Paladin

Famished Paladin doesn't untap during your untap step.
Whenever you gain life, untap Famished Paladin.

Swords to Plowshares

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

Suture Priest

Whenever another creature you control enters, you may gain 1 life.
Whenever a creature an opponent controls enters, you may have that player lose 1 life.

Voice of the Blessed

Whenever you gain life, put a +1/+1 counter on Voice of the Blessed.
As long as Voice of the Blessed has four or more +1/+1 counters on it, it has flying and vigilance.
As long as Voice of the Blessed has ten or more +1/+1 counters on it, it has indestructible.

Sign in Blood

Target player draws two cards and loses 2 life.

Resplendent Mentor

White creatures you control have "{T}: You gain 1 life."

Ajani's Pridemate

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

Sanguine Bond

Whenever you gain life, target opponent loses that much life.

Urborg, Tomb of Yawgmoth

Each land is a Swamp in addition to its other land types.

Scrubland

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.