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.)

Stern Judge

{T}: Each player loses 1 life for each Swamp they control.

Platinum Angel

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

Cloudsteel Kirin

Flying
Equipped creature has flying and "You can't lose the game and your opponents can't win the game."
Reconfigure {5} ({5}: Attach to target creature you control; or unattach from a creature. Reconfigure only as a sorcery. While attached, this isn't a creature.)

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.

Serra the Benevolent

+2: Creatures you control with flying get +1/+1 until end of turn.
−3: Create a 4/4 white Angel creature token with flying and vigilance.
−6: You get an emblem with "If you control a creature, damage that would reduce your life total to less than 1 reduces it to 1 instead."

Axis of Mortality

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

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."

Cleansing

For each land, destroy that land unless any player pays 1 life.

Blazing Hope

Exile target creature with power greater than or equal to your life total.

Angel of Grace

Flash
Flying
When Angel of Grace enters, until end of turn, damage that would reduce your life total to less than 1 reduces it to 1 instead.
{4}{W}{W}, Exile Angel of Grace from your graveyard: Your life total becomes 10.

Evra, Halcyon Witness

Lifelink
{4}: Exchange your life total with Evra, Halcyon Witness's power.

Soul Conduit

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

Sustaining Spirit

Cumulative upkeep {1}{W} (At the beginning of your upkeep, put an age counter on this permanent, then sacrifice it unless you pay its upkeep cost for each age counter on it.)
Damage that would reduce your life total to less than 1 reduces it to 1 instead.

Reverse the Sands

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

Exquisite Archangel

Flying
If you would lose the game, instead exile Exquisite Archangel and your life total becomes equal to your starting life total.

Life Matrix

{4}, {T}: Put a matrix counter on target creature and that creature gains "Remove a matrix counter from this creature: Regenerate this creature." Activate only during your upkeep.

Mirror Universe

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

Enlightened Tutor

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

Cradle of Vitality

Whenever you gain life, you may pay {1}{W}. If you do, put a +1/+1 counter on target creature for each 1 life you gained.

Angelic Enforcer

Flying
You have hexproof.
Angelic Enforcer's power and toughness are each equal to your life total.
Whenever Angelic Enforcer attacks, double your life total.

Enduring Angel

Flying, double strike
You have hexproof.
If your life total would be reduced to 0 or less, instead transform Enduring Angel and your life total becomes 3. Then if Enduring Angel didn't transform this way, you lose the game.

Enduring Angel // Angelic Enforcer

Worship

If you control a creature, damage that would reduce your life total to less than 1 reduces it to 1 instead.

The Book of Exalted Deeds

At the beginning of your end step, if you gained 3 or more life this turn, create a 3/3 white Angel creature token with flying.
{W}{W}{W}, {T}, Exile The Book of Exalted Deeds: Put an enlightened counter on target Angel. It gains "You can't lose the game and your opponents can't win the game." Activate only as a sorcery.

Near-Death Experience

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

Everybody Lives!

All creatures gain hexproof and indestructible until end of turn. Players gain hexproof until end of turn. Players can't lose life this turn and players can't lose the game or win the game this turn.

Herald of Eternal Dawn

Flash (You may cast this spell any time you could cast an instant.)
Flying
You can't lose the game and your opponents can't win the game.

Idyllic Tutor

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