Contaminated Ground

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

Hissing Miasma

Whenever a creature attacks you, its controller loses 1 life.

Artifact Possession

Enchant artifact
Whenever enchanted artifact becomes tapped or a player activates an ability of enchanted artifact without {T} in its activation cost, Artifact Possession deals 2 damage to that artifact's controller.

Triskaidekaphobia

At the beginning of your upkeep, choose one —
• Each player with exactly 13 life loses the game, then each player gains 1 life.
• Each player with exactly 13 life loses the game, then each player loses 1 life.

Crown of Doom

Whenever a creature attacks you or a planeswalker you control, it gets +2/+0 until end of turn.
{2}: Target player other than Crown of Doom's owner gains control of it. Activate only during your turn.

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.

Parasitic Impetus

Enchant creature
Enchanted creature gets +2/+2 and is goaded. (It attacks each combat if able and attacks a player other than you if able.)
Whenever enchanted creature attacks, its controller loses 2 life and you gain 2 life.

Ghoulish Impetus

Enchant creature
Enchanted creature gets +1/+1, has deathtouch, and is goaded.
When enchanted creature dies, return Ghoulish Impetus to the battlefield at the beginning of the next end step.

Lithoform Blight

Enchant land
When Lithoform Blight enters, draw a card.
Enchanted land loses all land types and abilities and has "{T}: Add {C}" and "{T}, Pay 1 life: Add one mana of any color."

Infectious Curse

Enchant player
Spells you cast that target enchanted player cost {1} less to cast.
At the beginning of enchanted player's upkeep, that player loses 1 life and you gain 1 life.

Accursed Witch

Spells your opponents cast that target Accursed Witch cost {1} less to cast.
When Accursed Witch dies, return it to the battlefield transformed under your control attached to target opponent.

Accursed Witch // Infectious Curse

Relic Bane

Enchant artifact
Enchanted artifact has "At the beginning of your upkeep, you lose 2 life."

Tatsunari, Toad Rider

Whenever you cast an enchantment spell, if you don't control a creature named Keimi, create Keimi, a legendary 3/3 black and green Frog creature token with "Whenever you cast an enchantment spell, each opponent loses 1 life and you gain 1 life."
{1}{G/U}: Tatsunari, Toad Rider and target Frog you control can't be blocked this turn except by creatures with flying or reach.

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.

Trespasser's Curse

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

Ragged Veins

Flash
Enchant creature
Whenever enchanted creature is dealt damage, its controller loses that much life.

Power Taint

Enchant enchantment
At the beginning of the upkeep of enchanted enchantment's controller, that player loses 2 life unless they pay {2}.
Cycling {2} ({2}, Discard this card: Draw a card.)

Visions of Brutality

Devoid (This card has no color.)
Enchant creature
Enchanted creature can't block.
Whenever enchanted creature deals damage, its controller loses that much life.

Painful Quandary

Whenever an opponent casts a spell, that player loses 5 life unless they discard a card.

Jinxed Choker

At the beginning of your end step, target opponent gains control of Jinxed Choker and puts a charge counter on it.
At the beginning of your upkeep, Jinxed Choker deals damage to you equal to the number of charge counters on it.
{3}: Put a charge counter on Jinxed Choker or remove one from it.

Pooling Venom

Enchant land
Whenever enchanted land becomes tapped, its controller loses 2 life.
{3}{B}: Destroy enchanted land.

Curse of Vengeance

Enchant player
Whenever enchanted player casts a spell, put a spite counter on Curse of Vengeance.
When enchanted player loses the game, you gain X life and draw X cards, where X is the number of spite counters on Curse of Vengeance.

Warp Artifact

Enchant artifact
At the beginning of the upkeep of enchanted artifact's controller, Warp Artifact deals 1 damage to that player.

Corrupted Roots

Enchant Forest or Plains
Whenever enchanted land becomes tapped, its controller loses 2 life.

Gonti's Machinations

Whenever you lose life for the first time each turn, you get {E}. (You get an energy counter. Damage causes loss of life.)
Pay {E}{E}, Sacrifice Gonti's Machinations: Each opponent loses 3 life. You gain life equal to the life lost this way.