Repay in Kind

Each player's life total becomes the lowest life total among all players.

Disenchant

Vault Skirge

({B/P} can be paid with either {B} or 2 life.)
Flying
Lifelink (Damage dealt by this creature also causes you to gain that much life.)

Phyrexian Unlife

You don't lose the game for having 0 or less life.
As long as you have 0 or less life, all damage is dealt to you as though its source had infect. (Damage is dealt to you in the form of poison counters.)

Dismember

({B/P} can be paid with either {B} or 2 life.)
Target creature gets -5/-5 until end of turn.

Tortured Existence

{B}, Discard a creature card: Return target creature card from your graveyard to your hand.

Unmake

Gitaxian Probe

({U/P} can be paid with either {U} or 2 life.)
Look at target player's hand.
Draw a card.

Argivian Find

Return target artifact or enchantment card from your graveyard to your hand.

Caves of Koilos

{T}: Add {C}.
{T}: Add {W} or {B}. Caves of Koilos deals 1 damage to you.

Pithing Needle

As Pithing Needle enters, choose a card name.
Activated abilities of sources with the chosen name can't be activated unless they're mana abilities.

Apostle's Blessing

({W/P} can be paid with either {W} or 2 life.)
Target artifact or creature you control gains protection from artifacts or from the color of your choice until end of turn.

Moon-Blessed Cleric

Divine Intervention — When Moon-Blessed Cleric enters, you may search your library for an enchantment card, reveal it, then shuffle and put that card on top.

Ghostly Prison

Creatures can't attack you unless their controller pays {2} for each creature they control that's attacking you.

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.)

Scourge of the Skyclaves

Kicker {4}{B}
When you cast this spell, if it was kicked, each player loses half their life, rounded up.
Scourge of the Skyclaves's power and toughness are each equal to 20 minus the highest life total among players.

Death's Shadow

Death's Shadow gets -X/-X, where X is your life total.

Plains

Porphyry Nodes

At the beginning of your upkeep, destroy the creature with the least power. It can't be regenerated. If two or more creatures are tied for least power, you choose one of them.
When there are no creatures on the battlefield, sacrifice Porphyry Nodes.

Swamp

Marrow Shards

({W/P} can be paid with either {W} or 2 life.)
Marrow Shards deals 1 damage to each attacking creature.

Cathedral Membrane

({W/P} can be paid with either {W} or 2 life.)
Defender
When Cathedral Membrane dies during combat, it deals 6 damage to each creature it blocked this combat.