Gandalf

Keeper of the Accord

At the beginning of each opponent's end step, if that player controls more creatures than you, create a 1/1 white Soldier creature token.
At the beginning of each opponent's end step, if that player controls more lands than you, you may search your library for a basic Plains card, put it onto the battlefield tapped, then shuffle.

Have

Unbreakable Formation

Creatures you control gain indestructible until end of turn.
Addendum — If you cast this spell during your main phase, put a +1/+1 counter on each of those creatures and they gain vigilance until end of turn.

Oketra's Monument

White creature spells you cast cost {1} less to cast.
Whenever you cast a creature spell, create a 1/1 white Warrior creature token with vigilance.

Tocasia's Welcome

Whenever one or more creatures you control with mana value 3 or less enter, draw a card. This ability triggers only once each turn.

Marble Diamond

Marble Diamond enters tapped.
{T}: Add {W}.

Loyal Warhound

Vigilance
When Loyal Warhound enters, if an opponent controls more lands than you, search your library for a basic Plains card, put it onto the battlefield tapped, then shuffle.

Rumor Gatherer

Alliance — Whenever another creature you control enters, scry 1. If this is the second time this ability has resolved this turn, draw a card instead.

Gandalf of the Secret Fire

Chromatic Orrery

You may spend mana as though it were mana of any color.
{T}: Add {C}{C}{C}{C}{C}.
{5}, {T}: Draw a card for each color among permanents you control.

Eagles of the North

Flying
When Eagles of the North enters, creatures you control get +1/+0 and gain first strike until end of turn.
Plainscycling {1} ({1}, Discard this card: Search your library for a Plains card, reveal it, put it into your hand, then shuffle.)

Clarion Spirit

Whenever you cast your second spell each turn, create a 1/1 white Spirit creature token with flying.

Braids

Nykthos, Shrine to Nyx

{T}: Add {C}.
{2}, {T}: Choose a color. Add an amount of mana of that color equal to your devotion to that color. (Your devotion to a color is the number of mana symbols of that color in the mana costs of permanents you control.)

Memnite

Austere Command

Choose two —
• Destroy all artifacts.
• Destroy all enchantments.
• Destroy all creatures with mana value 3 or less.
• Destroy all creatures with mana value 4 or greater.

Mentor of the Meek

Whenever another creature you control with power 2 or less enters, you may pay {1}. If you do, draw a card.

Sejiri Glacier

Sejiri Glacier enters tapped.
{T}: Add {W}.

Sejiri Shelter

Target creature you control gains protection from the color of your choice until end of turn.

Sejiri Shelter // Sejiri Glacier

Daxos, Blessed by the Sun

Daxos's toughness is equal to your devotion to white. (Each {W} in the mana costs of permanents you control counts toward your devotion to white.)
Whenever another creature you control enters or dies, you gain 1 life.

Cloudstone Curio

Whenever a nonartifact permanent you control enters, you may return another permanent you control that shares a permanent type with it to its owner's hand.

Phelddagrif

Hour of Revelation

This spell costs {3} less to cast if there are ten or more nonland permanents on the battlefield.
Destroy all nonland permanents.

Pearl Medallion

White spells you cast cost {1} less to cast.

Rescuer Chwinga

Flash
Natural Shelter — When Rescuer Chwinga enters, you may return another permanent you control to its owner's hand.

Stonecloaker

Flash
Flying
When Stonecloaker enters, return a creature you control to its owner's hand.
When Stonecloaker enters, exile target card from a graveyard.

Emeria, Shattered Skyclave

As Emeria, Shattered Skyclave enters, you may pay 3 life. If you don't, it enters tapped.
{T}: Add {W}.

Emeria's Call

Create two 4/4 white Angel Warrior creature tokens with flying. Non-Angel creatures you control gain indestructible until your next turn.

Emeria's Call // Emeria, Shattered Skyclave

Suture Priest

Whenever another creature you control enters, you may gain 1 life.
Whenever a creature an opponent controls enters, you may have that player lose 1 life.

Castle Ardenvale

Castle Ardenvale enters tapped unless you control a Plains.
{T}: Add {W}.
{2}{W}{W}, {T}: Create a 1/1 white Human creature token.

Heraldic Banner

As this artifact enters, choose a color.
Creatures you control of the chosen color get +1/+0.
{T}: Add one mana of the chosen color.

Cloud Key

As Cloud Key enters, choose artifact, creature, enchantment, instant, or sorcery.
Spells you cast of the chosen type cost {1} less to cast.

Luminous Phantom

Flying
Whenever another creature you control leaves the battlefield, you gain 1 life.
If Luminous Phantom would be put into a graveyard from anywhere, exile it instead.

Getting

Lunarch Veteran

Whenever another creature you control enters, you gain 1 life.
Disturb {1}{W} (You may cast this card from your graveyard transformed for its disturb cost.)

Lunarch Veteran // Luminous Phantom

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.

Shelter

Target creature you control gains protection from the color of your choice until end of turn.
Draw a card.

Weathered Wayfarer

{W}, {T}: Search your library for a land card, reveal it, put it into your hand, then shuffle. Activate only if an opponent controls more lands than you.

Soul Warden

Whenever another creature enters, you gain 1 life.

Cathars' Crusade

Whenever a creature you control enters, put a +1/+1 counter on each creature you control.

Knight of the White Orchid

First strike
When Knight of the White Orchid enters, if an opponent controls more lands than you, you may search your library for a Plains card, put it onto the battlefield, then shuffle.

Nacre Talisman

Whenever a player casts a white spell, you may pay {3}. If you do, untap target permanent.

Kabira Plateau

Kabira Plateau enters tapped.
{T}: Add {W}.

Kabira Takedown

Kabira Takedown deals damage equal to the number of creatures you control to target creature or planeswalker.

Kabira Takedown // Kabira Plateau

Plains

Semblance Anvil

Imprint — When Semblance Anvil enters, you may exile a nonland card from your hand.
Spells you cast that share a card type with the exiled card cost {2} less to cast.

Deep Gnome Terramancer

Flash
Mold Earth — Whenever one or more lands enter under an opponent's control without being played, you may search your library for a Plains card, put it onto the battlefield tapped, then shuffle. Do this only once each turn.

Sol Ring

Soul's Attendant

Whenever another creature enters, you may gain 1 life.

Generous Gift

Destroy target permanent. Its controller creates a 3/3 green Elephant creature token.

Cryptic Gateway

Tap two untapped creatures you control: You may put a creature card from your hand that shares a creature type with each creature tapped this way onto the battlefield.

Archaeomancer's Map

When Archaeomancer's Map enters, search your library for up to two basic Plains cards, reveal them, put them into your hand, then shuffle.
Whenever a land an opponent controls enters, if that player controls more lands than you, you may put a land card from your hand onto the battlefield.

Kor Skyfisher

Flying
When Kor Skyfisher enters, return a permanent you control to its owner's hand.

Emancipation Angel

Flying
When Emancipation Angel enters, return a permanent you control to its owner's hand.

Secret Fire

Reprieve

Return target spell to its owner's hand.
Draw a card.

Wall of Omens

Defender
When Wall of Omens enters, draw a card.

Indoctrination Attendant

Toxic 1 (Players dealt combat damage by this creature also get a poison counter.)
When Indoctrination Attendant enters, you may return another permanent you control to its owner's hand. If you do, create a 1/1 colorless Phyrexian Mite artifact creature token with toxic 1 and "This creature can't block."

Flowering of the White Tree

Legendary creatures you control get +2/+1 and have ward {1}.
Nonlegendary creatures you control get +1/+1.

Caged Sun

As Caged Sun enters, choose a color.
Creatures you control of the chosen color get +1/+1.
Whenever a land's ability causes you to add one or more mana of the chosen color, add one additional mana of that color.

Spirited Companion

When Spirited Companion enters, draw a card.

Don't Have

Rammas Echor, Ancient Shield

Whenever you cast your second spell each turn, draw a card, then create a 0/3 white Wall creature token with defender.
At the beginning of combat on your turn, creatures you control with defender gain exalted until end of turn. (Whenever a creature you control attacks alone, it gets +1/+1 until end of turn for each instance of exalted among permanents you control.)

Whitemane Lion

Flash
When Whitemane Lion enters, return a creature you control to its owner's hand.

Farewell

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

Witch-Blessed Meadow

As Witch-Blessed Meadow enters, you may pay 3 life. If you don't, it enters tapped.
{T}: Add {W}.

Witch Enchanter

When Witch Enchanter enters, destroy target artifact or enchantment an opponent controls.

Witch Enchanter // Witch-Blessed Meadow

Gandalf, White Rider

Vigilance
Whenever you cast a spell, creatures you control get +1/+0 until end of turn. Scry 1.
When Gandalf, White Rider dies, you may put it into its owner's library fifth from the top.

Makindi Mesas

Makindi Mesas enters tapped.
{T}: Add {W}.

Makindi Stampede

Creatures you control get +2/+2 until end of turn.

Makindi Stampede // Makindi Mesas

Path to Exile

Exile target creature. Its controller may search their library for a basic land card, put that card onto the battlefield tapped, then shuffle.

Dawn of a New Age

Dawn of a New Age enters with a hope counter on it for each creature you control.
At the beginning of your end step, remove a hope counter from Dawn of a New Age. If you do, draw a card. Then if Dawn of a New Age has no hope counters on it, sacrifice it and you gain 4 life.

Ajani's Welcome

Whenever a creature you control enters, you gain 1 life.

Ashnod's Altar

Ornithopter

Swords to Plowshares

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

Ondu Skyruins

Ondu Skyruins enters tapped.
{T}: Add {W}.

Ondu Inversion

Ondu Inversion // Ondu Skyruins

Welcoming Vampire

Flying
Whenever one or more other creatures you control with power 2 or less enter, draw a card. This ability triggers only once each turn.

Stormfront Riders

Flying
When Stormfront Riders enters, return two creatures you control to their owner's hand.
Whenever Stormfront Riders or another creature is returned to your hand from the battlefield, create a 1/1 white Soldier creature token.

Courageous Resolve

Up to one target creature you control gains protection from each of your opponents until end of turn. Draw a card. (It can't be blocked, targeted, dealt damage, enchanted, or equipped by anything controlled by those players.)
Fateful hour — If you have 5 or less life, you can't lose life this turn, you can't lose the game this turn, and your opponents can't win the game this turn.

God-Eternal Oketra

Double strike
Whenever you cast a creature spell, create a 4/4 black Zombie Warrior creature token with vigilance.
When God-Eternal Oketra dies or is put into exile from the battlefield, you may put it into its owner's library third from the top.

Blessed Sanctuary

Prevent all noncombat damage that would be dealt to you and creatures you control.
Whenever a nontoken creature you control enters, create a 2/2 white Unicorn creature token.

Defiler of Faith

Vigilance
As an additional cost to cast white permanent spells, you may pay 2 life. Those spells cost {W} less to cast if you paid life this way. This effect reduces only the amount of white mana you pay.
Whenever you cast a white permanent spell, create a 1/1 white Soldier creature token.

Karn

War Room

{T}: Add {C}.
{3}, {T}, Pay life equal to the number of colors in your commanders' color identity: Draw a card.