Fabled Passage

{T}, Sacrifice Fabled Passage: Search your library for a basic land card, put it onto the battlefield tapped, then shuffle. Then if you control four or more lands, untap that land.

Soul Warden

Whenever another creature enters, you gain 1 life.

Last Breath

Exile target creature with power 2 or less. Its controller gains 4 life.

Squadron Hawk

Flying
When Squadron Hawk enters, you may search your library for up to three cards named Squadron Hawk, reveal them, put them into your hand, then shuffle.

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.

Soul's Attendant

Whenever another creature enters, you may gain 1 life.

Plains

Rest for the Weary

Target player gains 4 life.
Landfall — If you had a land enter the battlefield under your control this turn, that player gains 8 life instead.

Rhox Faithmender

Lifelink (Damage dealt by this creature also causes you to gain that much life.)
If you would gain life, you gain twice that much life instead.

Kabira Crossroads

Kabira Crossroads enters tapped.
When Kabira Crossroads enters, you gain 2 life.
{T}: Add {W}.

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.

Serra Ascendant

Lifelink (Damage dealt by this creature also causes you to gain that much life.)
As long as you have 30 or more life, Serra Ascendant gets +5/+5 and has flying.

Fumigate

Destroy all creatures. You gain 1 life for each creature destroyed this way.

White Sun's Twilight

You gain X life. Create X 1/1 colorless Phyrexian Mite artifact creature tokens with toxic 1 and "This creature can't block." If X is 5 or more, destroy all other creatures. (Players dealt combat damage by a creature with toxic 1 also get a poison counter.)