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.)

Swift Reconfiguration

Flash
Enchant creature or Vehicle
Enchanted permanent is a Vehicle artifact with crew 5 and it loses all other card types. (It's not a creature unless it's crewed.)

Loran's Escape

Target artifact or creature gains hexproof and indestructible until end of turn. Scry 1.

Swords to Plowshares

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

Rescuer Chwinga

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

Alms Collector

Flash
If an opponent would draw two or more cards, instead you and that player each draw a card.

Aven Mindcensor

Flash
Flying
If an opponent would search a library, that player searches the top four cards of that library instead.

Masako the Humorless

Flash
Tapped creatures you control can block as though they were untapped.

Containment Priest

Flash
If a nontoken creature would enter and it wasn't cast, exile it instead.

Loyal Gryff

Flash
Flying
When this creature enters, you may return another creature you control to its owner's hand.

Seht's Tiger

Flash (You may cast this spell any time you could cast an instant.)
When this creature enters, you gain protection from the color of your choice until end of turn. (You can't be targeted, dealt damage, or enchanted by anything of the chosen color.)

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.

Whitemane Lion

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

Temporal Isolation

Flash
Enchant creature
Enchanted creature has shadow. (It can block or be blocked by only creatures with shadow.)
Prevent all damage that would be dealt by enchanted creature.

Marble Diamond

This artifact enters tapped.
{T}: Add {W}.

Aura of Silence

Artifact and enchantment spells your opponents cast cost {2} more to cast.
Sacrifice this enchantment: Destroy target artifact or enchantment.

Celestial Crusader

Flash
Split second (As long as this spell is on the stack, players can't cast spells or activate abilities that aren't mana abilities.)
Flying
Other white creatures get +1/+1.

White Sun's Zenith

Create X 2/2 white Cat creature tokens. Shuffle White Sun's Zenith into its owner's library.

Castle Ardenvale

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

Angel of Grace

Flash
Flying
When this creature enters, until end of turn, damage that would reduce your life total to less than 1 reduces it to 1 instead.
{4}{W}{W}, Exile this card from your graveyard: Your life total becomes 10.

Stroke of Midnight

Destroy target nonland permanent. Its controller creates a 1/1 white Human creature token.

Stasis Snare

Flash (You may cast this spell any time you could cast an instant.)
When this enchantment enters, exile target creature an opponent controls until this enchantment leaves the battlefield.

Drogskol Shieldmate

Flash
When this creature enters, other creatures you control get +0/+1 until end of turn.

Thought Vessel

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

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.

Archivist of Oghma

Flash
Whenever an opponent searches their library, you gain 1 life and draw a card.

Mind Stone

{T}: Add {C}.
{1}, {T}, Sacrifice this artifact: Draw a card.

Windbrisk Heights

Hideaway 4 (When this land enters, look at the top four cards of your library, exile one face down, then put the rest on the bottom in a random order.)
This land enters tapped.
{T}: Add {W}.
{W}, {T}: You may play the exiled card without paying its mana cost if you attacked with three or more creatures this turn.

Dictate of Heliod

Sol Ring

Star Compass

This artifact enters tapped.
{T}: Add one mana of any color that a basic land you control could produce.

Jeskai Barricade

Flash (You may cast this spell any time you could cast an instant.)
Defender
When this creature enters, you may return another target creature you control to its owner's hand.

Blacksmith's Skill

Target permanent gains hexproof and indestructible until end of turn. If it's an artifact creature, it gets +2/+2 until end of turn.

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.

Settle the Wreckage

Exile all attacking creatures target player controls. That player may search their library for that many basic land cards, put those cards onto the battlefield tapped, then shuffle.

Arcane Signet

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

Emeria, the Sky Ruin

This land enters tapped.
At the beginning of your upkeep, if you control seven or more Plains, you may return target creature card from your graveyard to the battlefield.
{T}: Add {W}.

Affa Guard Hound

Flash (You may cast this spell any time you could cast an instant.)
When this creature enters, target creature gets +0/+3 until end of turn.

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.

Darksteel Mutation

Enchant creature
Enchanted creature is an Insect artifact creature with base power and toughness 0/1 and has indestructible, and it loses all other abilities, card types, and creature types.

Idyllic Grange

({T}: Add {W}.)
This land enters tapped unless you control three or more other Plains.
When this land enters untapped, put a +1/+1 counter on target creature you control.

Generous Gift

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

Stonecloaker

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

War Room

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

Seal Away

Flash
When this enchantment enters, exile target tapped creature an opponent controls until this enchantment leaves the battlefield.

Rootborn Defenses

Populate. Creatures you control gain indestructible until end of turn. (To populate, create a token that's a copy of a creature token you control.)

Force of Virtue

If it's not your turn, you may exile a white card from your hand rather than pay this spell's mana cost.
Flash
Creatures you control get +1/+1.

Pearl Medallion

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

Selfless Squire

Flash
When this creature enters, prevent all damage that would be dealt to you this turn.
Whenever damage that would be dealt to you is prevented, put that many +1/+1 counters on this creature.

Archaeomancer's Map

When this artifact 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.

Heliod's Intervention

Choose one —
• Destroy X target artifacts and/or enchantments.
• Target player gains twice X life.

Angel of the Dire Hour

Flash
Flying
When this creature enters, if you cast it from your hand, exile all attacking creatures.

Plains

Fellwar Stone

{T}: Add one mana of any color that a land an opponent controls could produce.

Grand Crescendo

Create X 1/1 green and white Citizen creature tokens. Creatures you control gain indestructible until end of 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.

Glorious Protector

Flash
Flying
When this creature enters, you may exile any number of non-Angel creatures you control until this creature leaves the battlefield.
Foretell {2}{W}

Solitude

Flash
Lifelink
When this creature enters, exile up to one other target creature. That creature's controller gains life equal to its power.
Evoke—Exile a white card from your hand.

Coldsteel Heart

This artifact enters tapped.
As this artifact enters, choose a color.
{T}: Add one mana of the chosen color.

Rout

You may cast this spell as though it had flash if you pay {2} more to cast it. (You may cast it any time you could cast an instant.)
Destroy all creatures. They can't be regenerated.

Eiganjo, Seat of the Empire

{T}: Add {W}.
Channel — {2}{W}, Discard this card: It deals 4 damage to target attacking or blocking creature. This ability costs {1} less to activate for each legendary creature you control.

Guardian of Faith

Flash
Vigilance
When this creature enters, any number of other target creatures you control phase out. (Treat them and anything attached to them as though they don't exist until their controller's next turn.)

Idol of Oblivion

{T}: Draw a card. Activate only if you created a token this turn.
{8}, {T}, Sacrifice this artifact: Create a 10/10 colorless Eldrazi creature token.

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.

Samwise the Stouthearted

Flash
When Samwise enters, choose up to one target permanent card in your graveyard that was put there from the battlefield this turn. Return it to your hand. Then the Ring tempts you.

Wasteland

{T}: Add {C}.
{T}, Sacrifice this land: Destroy target nonbasic land.

Resolute Reinforcements

Flash (You may cast this spell any time you could cast an instant.)
When this creature enters, create a 1/1 white Soldier creature token.

Secure the Wastes

Create X 1/1 white Warrior creature tokens.

Cemetery Protector

Flash
When this creature enters, exile a card from a graveyard.
Whenever you play a land or cast a spell, if it shares a card type with the exiled card, create a 1/1 white Human creature token.

Sigrid, God-Favored

Flash
First strike, protection from God creatures
When Sigrid enters, exile up to one target attacking or blocking creature until Sigrid leaves the battlefield.

Dust Elemental

Flash (You may cast this spell any time you could cast an instant.)
Flying; fear (This creature can't be blocked except by artifact creatures and/or black creatures.)
When this creature enters, return three creatures you control to their owner's hand.

Call the Coppercoats

Strive — This spell costs {1}{W} more to cast for each target beyond the first.
Choose any number of target opponents. Create X 1/1 white Human Soldier creature tokens, where X is the number of creatures those opponents control.

Cathar Commando

Flash
{1}, Sacrifice this creature: Destroy target artifact or enchantment.

Gandalf the White

Flash
You may cast legendary spells and artifact spells as though they had flash.
If a legendary permanent or an artifact entering or leaving the battlefield causes a triggered ability of a permanent you control to trigger, that ability triggers an additional time.

Hall of Heliod's Generosity

{T}: Add {C}.
{1}{W}, {T}: Put target enchantment card from your graveyard on top of your library.