Soul Echo

Soul Echo enters with X echo counters on it.
You don't lose the game for having 0 or less life.
At the beginning of your upkeep, sacrifice Soul Echo if there are no echo counters on it. Otherwise, target opponent may choose that for each 1 damage that would be dealt to you until your next upkeep, you remove an echo counter from Soul Echo instead.

Children of Korlis

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

Lightning Greaves

Equipped creature has haste and shroud. (It can't be the target of spells or abilities.)
Equip {0}

Profane Tutor

Suspend 2—{1}{B} (Rather than cast this card from your hand, pay {1}{B} and exile it with two time counters on it. At the beginning of your upkeep, remove a time counter. When the last is removed, you may cast it without paying its mana cost.)
Search your library for a card, put that card into your hand, then shuffle.

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.

Debt to the Deathless

Each opponent loses two times X life. You gain life equal to the life lost this way.

Greven, Predator Captain

Menace
Greven, Predator Captain gets +X/+0, where X is the amount of life you've lost this turn.
Whenever Greven attacks, you may sacrifice another creature. If you do, you draw cards equal to that creature's power and you lose life equal to that creature's toughness.

Exsanguinate

Each opponent loses X life. You gain life equal to the life lost this way.

Worldly Tutor

Search your library for a creature card, reveal it, then shuffle and put the card on top.

Wall of Blood

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

Death Grasp

Death Grasp deals X damage to any target. You gain X life.

Axis of Mortality

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

Champion's Helm

Equipped creature gets +2/+2.
As long as equipped creature is legendary, it has hexproof. (It can't be the target of spells or abilities your opponents control.)
Equip {1}

Repay in Kind

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

Enlightened Tutor

Search your library for an artifact or enchantment card, reveal it, then shuffle and put that card on top.

Demonic Tutor

Search your library for a card, put that card into your hand, then shuffle.

Oketra's Last Mercy

Your life total becomes equal to your starting life total. Lands you control don't untap during your next untap step.

Jarad, Golgari Lich Lord

Jarad, Golgari Lich Lord gets +1/+1 for each creature card in your graveyard.
{1}{B}{G}, Sacrifice another creature: Each opponent loses life equal to the sacrificed creature's power.
Sacrifice a Swamp and a Forest: Return Jarad from your graveyard to your hand.

Sol Ring

Sylvan Tutor

Search your library for a creature card, reveal it, then shuffle and put that card on top.

Karlov of the Ghost Council

Whenever you gain life, put two +1/+1 counters on Karlov of the Ghost Council.
{W}{B}, Remove six +1/+1 counters from Karlov of the Ghost Council: Exile target creature.

Dark Ritual

Mayael's Aria

At the beginning of your upkeep, put a +1/+1 counter on each creature you control if you control a creature with power 5 or greater. Then you gain 10 life if you control a creature with power 10 or greater. Then you win the game if you control a creature with power 20 or greater.

Saskia the Unyielding

Vigilance, haste
As Saskia the Unyielding enters, choose a player.
Whenever a creature you control deals combat damage to a player, it deals that much damage to the chosen player.

Magus of the Mirror

{T}, Sacrifice Magus of the Mirror: Exchange life totals with target opponent. Activate only during your upkeep.

Cruel Tutor

Search your library for a card, then shuffle and put that card on top. You lose 2 life.

Vampiric Tutor

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.)

Idyllic Tutor

Search your library for an enchantment card, reveal it, put it into your hand, then shuffle.

Rhystic Tutor

Unless any player pays {2}, search your library for a card, put that card into your hand, then shuffle.

Swords to Plowshares

Exile target creature. Its controller gains life equal to its power.

Soul Conduit

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

Rite of Consumption

As an additional cost to cast this spell, sacrifice a creature.
Rite of Consumption deals damage equal to the sacrificed creature's power to target player or planeswalker. You gain life equal to the damage dealt this way.

Phyrexian Arena

At the beginning of your upkeep, you draw a card and you lose 1 life.

Phyrexian Processor

As Phyrexian Processor enters, pay any amount of life.
{4}, {T}: Create an X/X black Phyrexian Minion creature token, where X is the life paid as Phyrexian Processor entered.

Platinum Angel

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

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.

Rowan, Scion of War

Menace
{T}: Spells you cast this turn that are black and/or red cost {X} less to cast, where X is the amount of life you lost this turn. Activate only as a sorcery.

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."

Grim Tutor

Search your library for a card, put that card into your hand, then shuffle. You lose 3 life.