Pontiff of Blight

Extort (Whenever you cast a spell, you may pay {W/B}. If you do, each opponent loses 1 life and you gain that much life.)
Other creatures you control have extort. (If a creature has multiple instances of extort, each triggers separately.)

Prism Ring

As this artifact enters, choose a color.
Whenever you cast a spell of the chosen color, you gain 1 life.

Demon's Horn

Whenever a player casts a black spell, you may gain 1 life.

Consuming Vapors

Target player sacrifices a creature of their choice. You gain life equal to that creature's toughness.
Rebound (If you cast this spell from your hand, exile it as it resolves. At the beginning of your next upkeep, you may cast this card from exile without paying its mana cost.)

Death Watch

Enchant creature
When enchanted creature dies, its controller loses life equal to its power and you gain life equal to its toughness.

Witch of the Moors

Deathtouch
At the beginning of your end step, if you gained life this turn, each opponent sacrifices a creature of their choice and you return up to one target creature card from your graveyard to your hand.

Revenge of Ravens

Whenever a creature attacks you or a planeswalker you control, that creature's controller loses 1 life and you gain 1 life.

Snuff Out

If you control a Swamp, you may pay 4 life rather than pay this spell's mana cost.
Destroy target nonblack creature. It can't be regenerated.

Cabal Coffers

{2}, {T}: Add {B} for each Swamp you control.

Sangromancer

Flying
Whenever a creature an opponent controls dies, you may gain 3 life.
Whenever an opponent discards a card, you may gain 3 life.

Veinwitch Coven

Menace
Whenever you gain life, you may pay {B}. If you do, return target creature card from your graveyard to your hand.

Cabal Stronghold

{T}: Add {C}.
{3}, {T}: Add {B} for each basic Swamp you control.

Paradise Plume

As this artifact enters, choose a color.
Whenever a player casts a spell of the chosen color, you may gain 1 life.
{T}: Add one mana of the chosen color.

Ayara, First of Locthwain

Whenever Ayara or another black creature you control enters, each opponent loses 1 life and you gain 1 life.
{T}, Sacrifice another black creature: Draw a card.

Cling to Dust

Exile target card from a graveyard. If it was a creature card, you gain 3 life. Otherwise, you draw a card.
Escape—{3}{B}, Exile five other cards from your graveyard. (You may cast this card from your graveyard for its escape cost.)

Basilica Screecher

Flying
Extort (Whenever you cast a spell, you may pay {W/B}. If you do, each opponent loses 1 life and you gain that much life.)

Sanguine Bond

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

Midnight Banshee

Wither (This deals damage to creatures in the form of -1/-1 counters.)
At the beginning of your upkeep, put a -1/-1 counter on each nonblack creature.

Alhammarret's Archive

If you would gain life, you gain twice that much life instead.
If you would draw a card except the first one you draw in each of your draw steps, draw two cards instead.

Palace Siege

As this enchantment enters, choose Khans or Dragons.
• Khans — At the beginning of your upkeep, return target creature card from your graveyard to your hand.
• Dragons — At the beginning of your upkeep, each opponent loses 2 life and you gain 2 life.

Deathgreeter

Whenever another creature dies, you may gain 1 life.

Sorin's Vengeance

Sorin's Vengeance deals 10 damage to target player or planeswalker and you gain 10 life.

Profane Memento

Whenever a creature card is put into an opponent's graveyard from anywhere, you gain 1 life.

Staff of the Death Magus

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

Gray Merchant of Asphodel

When this creature enters, each opponent loses X life, where X is your devotion to black. You gain life equal to the life lost this way. (Each {B} in the mana costs of permanents you control counts toward your devotion to black.)

Marauding Blight-Priest

Whenever you gain life, each opponent loses 1 life.

Aetherflux Reservoir

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

Swift End

Destroy target creature or planeswalker. You lose 2 life. (Then exile this card. You may cast the creature later from exile.)

Murderous Rider

Lifelink
When this creature dies, put it on the bottom of its owner's library.

Murderous Rider // Swift End

Noxious Gearhulk

Menace
When this creature enters, you may destroy another target creature. If a creature is destroyed this way, you gain life equal to its toughness.

Tymaret, Chosen from Death

Tymaret's toughness is equal to your devotion to black. (Each {B} in the mana costs of permanents you control counts toward your devotion to black.)
{1}{B}: Exile up to two target cards from graveyards. You gain 1 life for each creature card exiled this way.

Tendrils of Corruption

Tendrils of Corruption deals X damage to target creature and you gain X life, where X is the number of Swamps you control.

Defiant Bloodlord

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

Defile

Target creature gets -1/-1 until end of turn for each Swamp you control.

Nyx Lotus

Nyx Lotus enters tapped.
{T}: Choose a color. Add an amount of mana of that color equal to your devotion to that color. (Your devotion to a color is the number of mana symbols of that color in the mana costs of permanents you control.)

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.

Urborg, Tomb of Yawgmoth

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

Malakir Familiar

Flying, deathtouch
Whenever you gain life, this creature gets +1/+1 until end of turn.

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.