Vito, Thorn of the Dusk Rose

Whenever you gain life, target opponent loses that much life.
{3}{B}{B}: Creatures you control gain lifelink until end of turn.

Exquisite Blood

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

Samite Herbalist

Whenever this creature becomes tapped, you gain 1 life and scry 1. (Look at the top card of your library. You may put that card on the bottom.)

Mind Drain

Target opponent discards two cards, mills a card, and loses 1 life. You gain 1 life. (To mill a card, a player puts the top card of their library into their graveyard.)

Fleshtaker

Whenever you sacrifice another creature, you gain 1 life and scry 1. (Look at the top card of your library. You may put that card on the bottom.)
{1}, Sacrifice another creature: This creature gets +2/+2 until end of turn.

Sigarda's Splendor

As this enchantment enters, note your life total.
At the beginning of your upkeep, draw a card if your life total is greater than or equal to the last noted life total for this enchantment. Then note your life total.
Whenever you cast a white spell, you gain 1 life.

Fetid Heath

{T}: Add {C}.
{W/B}, {T}: Add {W}{W}, {W}{B}, or {B}{B}.

Smothering Tithe

Whenever an opponent draws a card, that player may pay {2}. If the player doesn't, you create a Treasure token. (It's an artifact with "{T}, Sacrifice this token: Add one mana of any color.")

Blood Artist

Whenever this creature or another creature dies, target player loses 1 life and you gain 1 life.

Sanguine Bond

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

Speakeasy Server

Flying
When this creature enters, you gain 1 life for each other creature you control.

Attended Healer

Whenever you gain life for the first time each turn, create a 1/1 white Cat creature token.
{2}{W}: Another target Cleric gains lifelink until end of turn.

Land Tax

At the beginning of your upkeep, if an opponent controls more lands than you, you may search your library for up to three basic land cards, reveal them, put them into your hand, then shuffle.

Orah, Skyclave Hierophant

Lifelink
Whenever Orah or another Cleric you control dies, return target Cleric card with lesser mana value from your graveyard to the battlefield.

Isolated Chapel

This land enters tapped unless you control a Plains or a Swamp.
{T}: Add {W} or {B}.

Scoured Barrens

This land enters tapped.
When this land enters, you gain 1 life.
{T}: Add {W} or {B}.

Elas il-Kor, Sadistic Pilgrim

Deathtouch
Whenever another creature you control enters, you gain 1 life.
Whenever another creature you control dies, each opponent loses 1 life.

Soul Warden

Whenever another creature enters, you gain 1 life.

Kor Celebrant

Whenever this creature or another creature you control enters, you gain 1 life.

Swamp

Marauding Blight-Priest

Whenever you gain life, each opponent loses 1 life.

Cleric of Life's Bond

Whenever another Cleric you control enters, you gain 1 life.
Whenever you gain life for the first time each turn, put a +1/+1 counter on this creature.