Crypt Ghast

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.)
Whenever you tap a Swamp for mana, add an additional {B}.

Read the Bones

Scry 2, then draw two cards. You lose 2 life. (To scry 2, look at the top two cards of your library, then put any number of them on the bottom and the rest on top in any order.)

Selenia, Dark Angel

Flying
Pay 2 life: Return Selenia, Dark Angel to its owner's hand.

Children of Korlis

Sacrifice Children of Korlis: You gain life equal to the life you've lost this turn. (Damage causes loss of life.)

Tainted Sigil

{T}, Sacrifice Tainted Sigil: You gain life equal to the total life lost by all players this turn. (Damage causes loss of life.)

Near-Death Experience

At the beginning of your upkeep, if you have exactly 1 life, you win the game.

Utter End

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.

Angel's Grace

Split second (As long as this spell is on the stack, players can't cast spells or activate abilities that aren't mana abilities.)
You can't lose the game this turn and your opponents can't win the game this turn. Until end of turn, damage that would reduce your life total to less than 1 reduces it to 1 instead.

Sanguine Bond

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

Tainted Remedy

If an opponent would gain life, that player loses that much life instead.

Axis of Mortality

At the beginning of your upkeep, you may have two target players exchange life totals.

Vizkopa Guildmage

{1}{W}{B}: Target creature gains lifelink until end of turn.
{1}{W}{B}: Whenever you gain life this turn, each opponent loses that much life.

Arcane Signet

{T}: Add one mana of any color in your commander's color identity.

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 artifact: Add one mana of any color.")

Sign in Blood

Target player draws two cards and loses 2 life.

Soul Conduit

{6}, {T}: Two target players exchange life totals.

Greed

Pristine Talisman

Wall of Blood

Defender (This creature can't attack.)
Pay 1 life: Wall of Blood gets +1/+1 until end of turn.

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.)

Fumigate

Destroy all creatures. You gain 1 life for each creature destroyed this way.

Bolas's Citadel

You may look at the top card of your library any time.
You may play lands and cast spells from the top of your library. If you cast a spell this way, pay life equal to its mana value rather than pay its mana cost.
{T}, Sacrifice ten nonland permanents: Each opponent loses 10 life.

Ambition's Cost

You draw three cards and you lose 3 life.

K'rrik, Son of Yawgmoth

({B/P} can be paid with either {B} or 2 life.)
Lifelink
For each {B} in a cost, you may pay 2 life rather than pay that mana.
Whenever you cast a black spell, put a +1/+1 counter on K'rrik, Son of Yawgmoth.

Platinum Angel

Flying
You can't lose the game and your opponents can't win the game.

Exquisite Blood

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

Anguished Unmaking

Exile target nonland permanent. You lose 3 life.

Hatred

As an additional cost to cast this spell, pay X life.
Target creature gets +X/+0 until end of turn.

Necropotence

Skip your draw step.
Whenever you discard a card, exile that card from your graveyard.
Pay 1 life: Exile the top card of your library face down. Put that card into your hand at the beginning of your next end step.

Talisman of Hierarchy

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

Merciless Eviction

Choose one —
• Exile all artifacts.
• Exile all creatures.
• Exile all enchantments.
• Exile all planeswalkers.

Resolute Archangel

Flying
When Resolute Archangel enters, if your life total is less than your starting life total, it becomes equal to your starting life total.

Reverse the Sands

Redistribute any number of players' life totals. (Each of those players gets one life total back.)

Repay in Kind

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

Vilis, Broker of Blood

Flying
{B}, Pay 2 life: Target creature gets -1/-1 until end of turn.
Whenever you lose life, draw that many cards. (Damage causes loss of life.)

Tree of Perdition

Defender
{T}: Exchange target opponent's life total with Tree of Perdition's toughness.

Gideon of the Trials

+1: Until your next turn, prevent all damage target permanent would deal.
0: Until end of turn, Gideon of the Trials becomes a 4/4 Human Soldier creature with indestructible that's still a planeswalker. Prevent all damage that would be dealt to him this turn.
0: You get an emblem with "As long as you control a Gideon planeswalker, you can't lose the game and your opponents can't win the game."