Have

Righteous Valkyrie

Flying
Whenever another Angel or Cleric you control enters, you gain life equal to that creature's toughness.
As long as you have at least 7 life more than your starting life total, creatures you control get +2/+2.

Vito, Thorn of the Dusk Rose

Whenever you gain life, target opponent loses that much life.
{3}{B}{B}: Creatures you control gain lifelink until end of turn.

Getting

Ballroom

Ballroom enters tapped.
{T}: Add {W} or {B}.
{4}, {T}: Investigate. (Create a Clue token. It's an artifact with "{2}, Sacrifice this artifact: Draw a card.")

Pontiff of Blight

Extort (Whenever you cast a spell, you may pay {W/B}. If you do, each opponent loses 1 life and you gain that much life.)
Other creatures you control have extort. (If a creature has multiple instances of extort, each triggers separately.)

Perch Protection

Gift an extra turn (You may promise an opponent a gift as you cast this spell. If you do, they take an extra turn after this one.)
Create four 2/2 blue Bird creature tokens with flying. If the gift was promised, all permanents you control phase out, and until your next turn, your life total can't change and you gain protection from everything.
Exile Perch Protection.

Starscape Cleric

Offspring {2}{B} (You may pay an additional {2}{B} as you cast this spell. If you do, when this creature enters, create a 1/1 token copy of it.)
Flying
This creature can't block.
Whenever you gain life, each opponent loses 1 life.

Dismal Backwater

This land enters tapped.
When this land enters, you gain 1 life.
{T}: Add {U} or {B}.

Seraph Sanctuary

When Seraph Sanctuary enters, you gain 1 life.
Whenever an Angel you control enters, you gain 1 life.
{T}: Add {C}.

Don't Have

Gwaihir, Greatest of the Eagles

Flying
Whenever Gwaihir attacks, target attacking creature gains flying until end of turn.
At the beginning of each end step, if you gained 3 or more life this turn, create a 3/3 white Bird creature token with flying and "Whenever this creature attacks, target attacking creature gains flying until end of turn."

Raffine's Tower

({T}: Add {W}, {U}, or {B}.)
Raffine's Tower enters tapped.
Cycling {3} ({3}, Discard this card: Draw a card.)

Exquisite Blood

Whenever an opponent loses life, you gain that much life.

Tablet of the Guilds

As Tablet of the Guilds enters, choose two colors.
Whenever you cast a spell, if it's at least one of the chosen colors, you gain 1 life for each of the chosen colors it is.

Bloodthirsty Conqueror

Flying, deathtouch
Whenever an opponent loses life, you gain that much life. (Damage causes loss of life.)

Venser's Journal

You have no maximum hand size.
At the beginning of your upkeep, you gain 1 life for each card in your hand.

Leyline of Hope

If Leyline of Hope is in your opening hand, you may begin the game with it on the battlefield.
If you would gain life, you gain that much life plus 1 instead.
As long as you have at least 7 life more than your starting life total, creatures you control get +2/+2.

Light of Promise

Enchant creature
Enchanted creature has "Whenever you gain life, put that many +1/+1 counters on this creature."

Tenured Inkcaster

When Tenured Inkcaster enters, put a +1/+1 counter on target creature.
Whenever a creature you control with a +1/+1 counter on it attacks, each opponent loses 1 life and you gain 1 life.

Scoured Barrens

This land enters tapped.
When this land enters, you gain 1 life.
{T}: Add {W} or {B}.

Azor, the Lawbringer

Flying
When Azor, the Lawbringer enters, each opponent can't cast instant or sorcery spells during that player's next turn.
Whenever Azor attacks, you may pay {X}{W}{U}{U}. If you do, you gain X life and draw X cards.

Tranquil Cove

This land enters tapped.
When this land enters, you gain 1 life.
{T}: Add {W} or {U}.

Orzhov Basilica

Orzhov Basilica enters tapped.
When Orzhov Basilica enters, return a land you control to its owner's hand.
{T}: Add {W}{B}.

Enduring Tenacity

Whenever you gain life, target opponent loses that much life.
When Enduring Tenacity dies, if it was a creature, return it to the battlefield under its owner's control. It's an enchantment. (It's not a creature.)

Etherwrought Page

At the beginning of your upkeep, choose one —
• You gain 2 life.
• Surveil 1. (Look at the top card of your library. You may put that card into your graveyard.)
• Each opponent loses 1 life.

Exemplar of Light

Flying
Whenever you gain life, put a +1/+1 counter on this creature.
Whenever you put one or more +1/+1 counters on this creature, draw a card. This ability triggers only once each turn.

Celestial Force

At the beginning of each upkeep, you gain 3 life.

Queza, Augur of Agonies

Whenever you draw a card, target opponent loses 1 life and you gain 1 life.

Sphinx of the Revelation

Flying, lifelink
Whenever you gain life, you get that many {E} (energy counters).
{W}{U}{U}, {T}, Pay X {E}: Draw X cards.

Drana's Emissary

Flying
At the beginning of your upkeep, each opponent loses 1 life and you gain 1 life.

Recumbent Bliss

Enchant creature
Enchanted creature can't attack or block.
At the beginning of your upkeep, you may gain 1 life.

Amalia Benavides Aguirre

Ward—Pay 3 life.
Whenever you gain life, Amalia Benavides Aguirre explores. Then destroy all other creatures if its power is exactly 20. (To have this creature explore, reveal the top card of your library. Put that card into your hand if it's a land. Otherwise, put a +1/+1 counter on this creature, then put the card back or put it into your graveyard.)

Field-Tested Frying Pan

When Field-Tested Frying Pan enters, create a Food token, then create a 1/1 white Halfling creature token and attach Field-Tested Frying Pan to it.
Equipped creature has "Whenever you gain life, this creature gets +X/+X until end of turn, where X is the amount of life you gained."
Equip {2}

Swamp

Exsanguinate

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

Silverquill Campus

Silverquill Campus enters tapped.
{T}: Add {W} or {B}.
{4}, {T}: Scry 1.

Archangel of Thune

Flying
Lifelink (Damage dealt by this creature also causes you to gain that much life.)
Whenever you gain life, put a +1/+1 counter on each creature you control.

Island

Heliod, Sun-Crowned

Indestructible
As long as your devotion to white is less than five, Heliod isn't a creature.
Whenever you gain life, put a +1/+1 counter on target creature or enchantment you control.
{1}{W}: Another target creature gains lifelink until end of turn.

Treasury Thrull

Extort (Whenever you cast a spell, you may pay {W/B}. If you do, each opponent loses 1 life and you gain that much life.)
Whenever Treasury Thrull attacks, you may return target artifact, creature, or enchantment card from your graveyard to your hand.

Indulging Patrician

Flying
Lifelink (Damage dealt by this creature also causes you to gain that much life.)
At the beginning of your end step, if you gained 3 or more life this turn, each opponent loses 3 life.

Kaya's Guile

Choose two —
• Each opponent sacrifices a creature of their choice.
• Exile all opponents' graveyards.
• Create a 1/1 white and black Spirit creature token with flying.
• You gain 4 life.
Entwine {3} (Choose all if you pay the entwine cost.)

Sanguine Bond

Whenever you gain life, target opponent loses that much life.

Voice of the Blessed

Whenever you gain life, put a +1/+1 counter on Voice of the Blessed.
As long as Voice of the Blessed has four or more +1/+1 counters on it, it has flying and vigilance.
As long as Voice of the Blessed has ten or more +1/+1 counters on it, it has indestructible.

Sunscorch Regent

Flying
Whenever an opponent casts a spell, put a +1/+1 counter on Sunscorch Regent and you gain 1 life.

Paladin of Prahv

Whenever Paladin of Prahv deals damage, you gain that much life.
Forecast — {1}{W}, Reveal Paladin of Prahv from your hand: Whenever target creature deals damage this turn, you gain that much life. (Activate only during your upkeep and only once each turn.)

Farewell

Choose one or more —
• Exile all artifacts.
• Exile all creatures.
• Exile all enchantments.
• Exile all graveyards.

Arcane Signet

{T}: Add one mana of any color in your commander's color identity.

Vigil for the Lost

Whenever a creature you control dies, you may pay {X}. If you do, you gain X life.

Hallow

Prevent all damage target spell would deal this turn. You gain life equal to the damage prevented this way.

Ghostly Prison

Creatures can't attack you unless their controller pays {2} for each creature they control that's attacking you.

Witch's Clinic

{T}: Add {C}.
{2}, {T}: Target commander gains lifelink until end of turn.

Essence Pulse

You gain 2 life. Each creature gets -X/-X until end of turn, where X is the amount of life you gained this turn.

Restless Fortress

Restless Fortress enters tapped.
{T}: Add {W} or {B}.
{2}{W}{B}: Restless Fortress becomes a 1/4 white and black Nightmare creature until end of turn. It's still a land.
Whenever Restless Fortress attacks, defending player loses 2 life and you gain 2 life.

Evolving Wilds

{T}, Sacrifice this land: Search your library for a basic land card, put it onto the battlefield tapped, then shuffle.

Shineshadow Snarl

As Shineshadow Snarl enters, you may reveal a Plains or Swamp card from your hand. If you don't, Shineshadow Snarl enters tapped.
{T}: Add {W} or {B}.

Prophetic Prism

When Prophetic Prism enters, draw a card.
{1}, {T}: Add one mana of any color.

Sejiri Refuge

Sejiri Refuge enters tapped.
When Sejiri Refuge enters, you gain 1 life.
{T}: Add {W} or {U}.

Victory's Herald

Flying
Whenever Victory's Herald attacks, attacking creatures gain flying and lifelink until end of turn.

Arcane Sanctum

Arcane Sanctum enters tapped.
{T}: Add {W}, {U}, or {B}.

Emergency Powers

Each player shuffles their hand and graveyard into their library, then draws seven cards. Exile Emergency Powers.
Addendum — If you cast this spell during your main phase, you may put a permanent card with mana value 7 or less from your hand onto the battlefield.

Serra Avatar

Serra Avatar's power and toughness are each equal to your life total.
When Serra Avatar is put into a graveyard from anywhere, shuffle it into its owner's library.

Dovin's Acuity

When Dovin's Acuity enters, you gain 2 life and draw a card.
Whenever you cast an instant spell during your main phase, you may return Dovin's Acuity to its owner's hand.

Wall of Reverence

Defender, flying
At the beginning of your end step, you may gain life equal to the power of target creature you control.

Aetherflux Reservoir

Whenever you cast a spell, you gain 1 life for each spell you've cast this turn.
Pay 50 life: Aetherflux Reservoir deals 50 damage to any target.

Faithful Mending

You gain 2 life, draw two cards, then discard two cards.
Flashback {1}{W}{U} (You may cast this card from your graveyard for its flashback cost. Then exile it.)

Thought Vessel

You have no maximum hand size.
{T}: Add {C}.

Temple of Silence

This land enters tapped.
When this land enters, scry 1. (Look at the top card of your library. You may put that card on the bottom.)
{T}: Add {W} or {B}.

Glacial Fortress

Glacial Fortress enters tapped unless you control a Plains or an Island.
{T}: Add {W} or {U}.

Ajani's Pridemate

Whenever you gain life, put a +1/+1 counter on this creature.

Fall of the Gavel

Sphinx's Insight

Draw two cards.
Addendum — If you cast this spell during your main phase, you gain 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.

Bloodthirsty Aerialist

Flying
Whenever you gain life, put a +1/+1 counter on Bloodthirsty Aerialist.

Void Rend

This spell can't be countered.
Destroy target nonland permanent.

Pristine Talisman

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.

Elenda, Saint of Dusk

Lifelink, hexproof from instants
As long as your life total is greater than your starting life total, Elenda gets +1/+1 and has menace. Elenda gets an additional +5/+5 as long as your life total is at least 10 greater than your starting life total.

Fiendish Panda

Whenever you gain life, put a +1/+1 counter on this creature.
When this creature dies, return another target non-Bear creature card with mana value less than or equal to this creature's power from your graveyard to the battlefield.

Spirit Loop

Enchant creature you control
Whenever enchanted creature deals damage, you gain that much life.
When Spirit Loop is put into a graveyard from the battlefield, return Spirit Loop to its owner's hand.

Authority of the Consuls

Creatures your opponents control enter tapped.
Whenever a creature an opponent controls enters, you gain 1 life.

Karlov of the Ghost Council

Whenever you gain life, put two +1/+1 counters on Karlov of the Ghost Council.
{W}{B}, Remove six +1/+1 counters from Karlov of the Ghost Council: Exile target creature.

Punish Ignorance

Counter target spell. Its controller loses 3 life and you gain 3 life.

Propaganda

Caduceus, Staff of Hermes

Equipped creature has lifelink.
As long as you have 30 or more life, equipped creature gets +5/+5 and has indestructible and "Prevent all damage that would be dealt to this creature."
Equip {W}{W}

Death Grasp

Death Grasp deals X damage to any target. You gain X life.

Supreme Verdict

This spell can't be countered.
Destroy all creatures.

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.

Orzhov Signet

Test of Endurance

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

Citadel Gate

Citadel Gate enters tapped.
As Citadel Gate enters, choose a color other than white.
{T}: Add {W} or one mana of the chosen color.

Kiss of the Amesha

Target player gains 7 life and draws two cards.

Paradise Plume

As Paradise Plume enters, choose a color.
Whenever a player casts a spell of the chosen color, you may gain 1 life.
{T}: Add one mana of the chosen color.

Swords to Plowshares

Exile target creature. Its controller gains life equal to its power.

Dromar's Cavern

When Dromar's Cavern enters, sacrifice it unless you return a non-Lair land you control to its owner's hand.
{T}: Add {W}, {U}, or {B}.

Vizkopa Guildmage

{1}{W}{B}: Target creature gains lifelink until end of turn.
{1}{W}{B}: Whenever you gain life this turn, each opponent loses that much life.

Riot Control

You gain 1 life for each creature your opponents control. Prevent all damage that would be dealt to you this turn.

Kabira Crossroads

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

Creeping Bloodsucker

At the beginning of your upkeep, Creeping Bloodsucker deals 1 damage to each opponent. You gain life equal to the damage dealt this way.

Beacon of Immortality

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

Vault of the Archangel

{T}: Add {C}.
{2}{W}{B}, {T}: Creatures you control gain deathtouch and lifelink until end of turn.

Essence Harvest

Target player loses X life and you gain X life, where X is the greatest power among creatures you control.

Gollum, Obsessed Stalker

Skulk (This creature can't be blocked by creatures with greater power.)
At the beginning of your end step, each opponent dealt combat damage this game by a creature named Gollum, Obsessed Stalker loses life equal to the amount of life you gained this turn.

The Magic Mirror

This spell costs {1} less to cast for each instant and sorcery card in your graveyard.
You have no maximum hand size.
At the beginning of your upkeep, put a knowledge counter on The Magic Mirror, then draw a card for each knowledge counter on The Magic Mirror.