Sengir, the Dark Baron

Flying
Whenever another creature dies, put two +1/+1 counters on Sengir, the Dark Baron.
Whenever another player loses the game, you gain life equal to that player's life total as the turn began.
Partner (You can have two commanders if both have partner.)

Mirror Universe

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

Beacon of Immortality

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

Celestial Convergence

Celestial Convergence enters the battlefield with seven omen counters on it.
At the beginning of your upkeep, remove an omen counter from Celestial Convergence. If there are no omen counters on Celestial Convergence, the player with the highest life total wins the game. If two or more players are tied for highest life total, the game is a draw.

Scourge of the Skyclaves

Kicker {4}{B}
When you cast this spell, if it was kicked, each player loses half their life, rounded up.
Scourge of the Skyclaves's power and toughness are each equal to 20 minus the highest life total among players.

Soul Conduit

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

Axis of Mortality

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

Oloro, Ageless Ascetic

At the beginning of your upkeep, you gain 2 life.
Whenever you gain life, you may pay {1}. If you do, draw a card and each opponent loses 1 life.
At the beginning of your upkeep, if Oloro, Ageless Ascetic is in the command zone, you gain 2 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.)

Drain Life

Spend only black mana on X.
Drain Life deals X damage to any target. You gain life equal to the damage dealt, but not more life than the player's life total before the damage was dealt, the planeswalker's loyalty before the damage was dealt, or the creature's toughness.

Speaker of the Heavens

Vigilance, lifelink
{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.

Dark Depths

Dark Depths enters the battlefield with ten ice counters on it.
{3}: Remove an ice counter from Dark Depths.
When Dark Depths has no ice counters on it, sacrifice it. If you do, create Marit Lage, a legendary 20/20 black Avatar creature token with flying and indestructible.

Exsanguinate

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

Teferi's Protection

Until your next turn, your life total can't change and you gain protection from everything. All permanents you control phase out. (While they're phased out, they're treated as though they don't exist. They phase in before you untap during your untap step.)
Exile Teferi's Protection.

Reverse the Sands

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

Aether Snap

Remove all counters from all permanents and exile all tokens.

Illusions of Grandeur

Cumulative upkeep {2} (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.)
When Illusions of Grandeur enters the battlefield, you gain 20 life.
When Illusions of Grandeur leaves the battlefield, you lose 20 life.

Vampire Hexmage

First strike
Sacrifice Vampire Hexmage: Remove all counters from target permanent.

Sigarda's Splendor

As Sigarda's Splendor enters the battlefield, note your life total.
At the beginning of your upkeep, draw a card if your life total is greater than or equal to the last noted life total for Sigarda's Splendor. Then note your life total.
Whenever you cast a white spell, you gain 1 life.

Magister Sphinx

Flying
When Magister Sphinx enters the battlefield, target player's life total becomes 10.

Paradox Haze

Enchant player
At the beginning of enchanted player's first upkeep each turn, that player gets an additional upkeep step after this step.

Tainted Remedy

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

Repay in Kind

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

Thespian's Stage

{T}: Add {C}.
{2}, {T}: Thespian's Stage becomes a copy of target land, except it has this ability.

Magus of the Mirror

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

Angel of Destiny

Flying, double strike
Whenever a creature you control deals combat damage to a player, you and that player each gain that much life.
At the beginning of your end step, if you have at least 15 life more than your starting life total, each player Angel of Destiny attacked this turn loses the game.