Curse of Vitality

Enchant player
Whenever enchanted player is attacked, you gain 2 life. Each opponent attacking that player does the same.

Felidar Sovereign

Vigilance (Attacking doesn't cause this creature to tap.)
Lifelink (Damage dealt by this creature also causes you to gain that much life.)
At the beginning of your upkeep, if you have 40 or more life, you win the game.

Test of Endurance

At the beginning of your upkeep, if you have 50 or more life, you win the game.

Arbiter of Knollridge

Vigilance
When Arbiter of Knollridge enters, each player's life total becomes the highest life total among all players.

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.

Approach of the Second Sun

If this spell was cast from your hand and you've cast another spell named Approach of the Second Sun this game, you win the game. Otherwise, put Approach of the Second Sun into its owner's library seventh from the top and you gain 7 life.

Temporary Truce

Each player may draw up to two cards. For each card less than two a player draws this way, that player gains 2 life.

Alhammarret's Archive

If you would gain life, you gain twice that much life instead.
If you would draw a card except the first one you draw in each of your draw steps, draw two cards instead.

Truce

Reward the Faithful

Any number of target players each gain life equal to the highest mana value among permanents you control.

Kwain, Itinerant Meddler

{T}: Each player may draw a card, then each player who drew a card this way gains 1 life.

Wedding Ring

When Wedding Ring enters, if it was cast, target opponent creates a token that's a copy of it.
Whenever an opponent who controls an artifact named Wedding Ring draws a card during their turn, you draw a card.
Whenever an opponent who controls an artifact named Wedding Ring gains life during their turn, you gain that much life.

Celestial Convergence

Celestial Convergence enters 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.

Bounty Board

{T}: Add one mana of any color.
{1}, {T}: Put a bounty counter on target creature. Activate only as a sorcery.
Whenever a creature with a bounty counter on it dies, each of its controller's opponents draws a card and gains 2 life.