Beacon of Immortality

Double target player's life total. Shuffle Beacon of Immortality into its owner's library.

Eternity Vessel

Eternity Vessel enters with X charge counters on it, where X is your life total.
Landfall — Whenever a land you control enters, you may have your life total become the number of charge counters on Eternity Vessel.

Speaker of the Heavens

Vigilance, lifelink (Attacking doesn't cause this creature to tap. Damage dealt by this creature also causes you to gain that much life.)
{T}: Create a 4/4 white Angel creature token with flying. Activate only if you have at least 7 life more than your starting life total and only as a sorcery.

Cosmos Elixir

At the beginning of your end step, draw a card if your life total is greater than your starting life total. Otherwise, you gain 2 life.

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.

Chainer's Torment

(As this Saga enters and after your draw step, add a lore counter. Sacrifice after III.)
I, II — Chainer's Torment deals 2 damage to each opponent and you gain 2 life.
III — Create an X/X black Nightmare Horror creature token, where X is half your life total, rounded up. It deals X damage to you.

Tree of Redemption

Defender
{T}: Exchange your life total with Tree of Redemption's toughness.

Axis of Mortality

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

Chalice of Death

Chalice of Life

{T}: You gain 1 life. Then if you have at least 10 life more than your starting life total, transform Chalice of Life.

Chalice of Life // Chalice of Death

Exquisite Archangel

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

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.

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.

Evra, Halcyon Witness

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

Celestial Mantle

Enchant creature
Enchanted creature gets +3/+3.
Whenever enchanted creature deals combat damage to a player, double its controller's life total.

Soul Conduit

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

Tree of Perdition

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