Night Market Lookout

Whenever Night Market Lookout becomes tapped, each opponent loses 1 life and you gain 1 life.

Stab Wound

Enchant creature
Enchanted creature gets -2/-2.
At the beginning of the upkeep of enchanted creature's controller, that player loses 2 life.

Duress

Target opponent reveals their hand. You choose a noncreature, nonland card from it. That player discards that card.

Agate-Blade Assassin

Whenever Agate-Blade Assassin attacks, defending player loses 1 life and you gain 1 life.

Contaminated Ground

Enchant land
Enchanted land is a Swamp.
Whenever enchanted land becomes tapped, its controller loses 2 life.

Cuombajj Witches

{T}: Cuombajj Witches deals 1 damage to any target and 1 damage to any target of an opponent's choice.

Crypt Rats

{X}: Crypt Rats deals X damage to each creature and each player. Spend only black mana on X.

Nezumi Road Captain

Menace
Vehicles you control have menace. (They can't be blocked except by two or more creatures.)

Okiba Reckoner Raid

(As this Saga enters and after your draw step, add a lore counter.)
I, II — Each opponent loses 1 life and you gain 1 life.
III — Exile this Saga, then return it to the battlefield transformed under your control.

Okiba Reckoner Raid // Nezumi Road Captain

Serrated Scorpion

When Serrated Scorpion dies, it deals 2 damage to each opponent and you gain 2 life.

Balemurk Leech

Eerie — Whenever an enchantment you control enters and whenever you fully unlock a Room, each opponent loses 1 life.

Sinister Possession

Enchant creature
Whenever enchanted creature attacks or blocks, its controller loses 2 life.

Trespasser's Curse

Enchant player
Whenever a creature enchanted player controls enters, that player loses 1 life and you gain 1 life.

Arrogant Outlaw

When Arrogant Outlaw enters, if an opponent lost life this turn, each opponent loses 2 life and you gain 2 life.

Unearth

Return target creature card with mana value 3 or less from your graveyard to the battlefield.
Cycling {2} ({2}, Discard this card: Draw a card.)

Village Rites

As an additional cost to cast this spell, sacrifice a creature.
Draw two cards.

Clawing Torment

Enchant artifact or creature
As long as enchanted permanent is a creature, it gets -1/-1 and can't block.
Enchanted permanent has "At the beginning of your upkeep, you lose 1 life."

Gray Merchant of Asphodel

When Gray Merchant of Asphodel 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.)

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.

Phyrexian Rager

When Phyrexian Rager enters, you draw a card and you lose 1 life.

Dusk Legion Zealot

When Dusk Legion Zealot enters, you draw a card and you lose 1 life.

Vampire Spawn

When this creature enters, each opponent loses 2 life and you gain 2 life.

Defile

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

Deadly Dispute

As an additional cost to cast this spell, sacrifice an artifact or creature.
Draw two cards and create a Treasure token. (It's an artifact with "{T}, Sacrifice this artifact: Add one mana of any color.")

Perilous Myr

When Perilous Myr dies, it deals 2 damage to any target.

Contaminated Bond

Enchant creature (Target a creature as you cast this. This card enters attached to that creature.)
Whenever enchanted creature attacks or blocks, its controller loses 3 life.