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.

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.

Repay in Kind

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

Magus of the Mirror

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

Soul Conduit

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

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.

Profane Transfusion

Two target players exchange life totals. You create an X/X colorless Horror artifact creature token, where X is the difference between those players' life totals.

Stunning Reversal

The next time you would lose the game this turn, instead draw seven cards and your life total becomes 1.
Exile Stunning Reversal.

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.)

Axis of Mortality

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

Courageous Resolve

Up to one target creature you control gains protection from each of your opponents until end of turn. Draw a card. (It can't be blocked, targeted, dealt damage, enchanted, or equipped by anything controlled by those players.)
Fateful hour — If you have 5 or less life, you can't lose life this turn, you can't lose the game this turn, and your opponents can't win the game this turn.

Angelic Enforcer

Flying
You have hexproof.
Angelic Enforcer's power and toughness are each equal to your life total.
Whenever this creature 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 this creature and your life total becomes 3. Then if this creature didn't transform this way, you lose the game.

Enduring Angel // Angelic Enforcer

Gallowbraid

Trample
Cumulative upkeep—Pay 1 life. (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.)

Netherborn Altar

{T}, Put a soul counter on this artifact: Put your commander into your hand from the command zone. Then you lose 3 life for each soul counter on this artifact.

Arbiter of Knollridge

Vigilance
When this creature enters, each player's life total becomes the highest life total among all players.

Angel of Grace

Flash
Flying
When this creature 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 this card from your graveyard: Your life total becomes 10.

Exquisite Archangel

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

Lich's Mirror

If you would lose the game, instead shuffle your hand, your graveyard, and all permanents you own into your library, then draw seven cards and your life total becomes 20.

Platinum Angel

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

The Golden Throne

Arcane Life-support — If you would lose the game, instead exile The Golden Throne and your life total becomes 1.
A Thousand Souls Die Every Day — {T}, Sacrifice a creature: Add three mana in any combination of colors.