Watcher of the Spheres

Flying
Creature spells with flying you cast cost {1} less to cast.
Whenever another creature you control with flying enters, Watcher of the Spheres gets +1/+1 until end of turn.

Hindering Light

Counter target spell that targets you or a permanent you control.
Draw a card.

Cast Out

Flash
When Cast Out enters, exile target nonland permanent an opponent controls until Cast Out leaves the battlefield.
Cycling {W} ({W}, Discard this card: Draw a card.)

Sky Diamond

Commander's Sphere

{T}: Add one mana of any color in your commander's color identity.
Sacrifice Commander's Sphere: Draw a card.

Hunted Lammasu

Flying
When Hunted Lammasu enters, target opponent creates a 4/4 black Horror 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.

Plains

Conclave Tribunal

Convoke (Your creatures can help cast this spell. Each creature you tap while casting this spell pays for {1} or one mana of that creature's color.)
When Conclave Tribunal enters, exile target nonland permanent an opponent controls until Conclave Tribunal leaves the battlefield.

Banishing Knack

Until end of turn, target creature gains "{T}: Return target nonland permanent to its owner's hand."

Port Town

As Port Town enters, you may reveal a Plains or Island card from your hand. If you don't, Port Town enters tapped.
{T}: Add {W} or {U}.

Baffling End

When Baffling End enters, exile target creature an opponent controls with mana value 3 or less.
When Baffling End leaves the battlefield, target opponent creates a 3/3 green Dinosaur creature token with trample.

Chart a Course

Draw two cards. Then discard a card unless you attacked this turn.

Siani, Eye of the Storm

Flying
Whenever Siani, Eye of the Storm attacks, scry X, where X is the number of attacking creatures with flying.
Partner (You can have two commanders if both have partner.)

Skycloud Expanse

Seal of Cleansing

Sacrifice Seal of Cleansing: Destroy target artifact or enchantment.

Pendant of Prosperity

Pendant of Prosperity enters under the control of an opponent of your choice.
{2}, {T}: Draw a card, then you may put a land card from your hand onto the battlefield. Pendant of Prosperity's owner draws a card, then that player may put a land card from their hand onto the battlefield.

Faerie Seer

Kumena's Awakening

Ascend (If you control ten or more permanents, you get the city's blessing for the rest of the game.)
At the beginning of your upkeep, each player draws a card. If you have the city's blessing, instead only you draw a card.

Irrigated Farmland

({T}: Add {W} or {U}.)
Irrigated Farmland enters tapped.
Cycling {2} ({2}, Discard this card: Draw a card.)

Marble Diamond

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

Azorius Keyrune

{T}: Add {W} or {U}.
{W}{U}: Azorius Keyrune becomes a 2/2 white and blue Bird artifact creature with flying until end of turn.

Island

Isperia, Supreme Judge

Flying
Whenever a creature attacks you or a planeswalker you control, you may draw a card.

Angelic Ascension

Exile target creature or planeswalker. Its controller creates a 4/4 white Angel creature token with flying.

Dovin, Grand Arbiter

+1: Until end of turn, whenever a creature you control deals combat damage to a player, put a loyalty counter on Dovin, Grand Arbiter.
−1: Create a 1/1 colorless Thopter artifact creature token with flying. You gain 1 life.
−7: Look at the top ten cards of your library. Put three of them into your hand and the rest on the bottom of your library in a random order.

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.)
Windbrisk Heights 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.

Ornithopter of Paradise

Sephara, Sky's Blade

You may pay {W} and tap four untapped creatures you control with flying rather than pay this spell's mana cost.
Flying, lifelink
Other creatures you control with flying have indestructible. (Damage and effects that say "destroy" don't destroy them.)

Winged Words

This spell costs {1} less to cast if you control a creature with flying.
Draw two cards.

Oblivion Ring

When Oblivion Ring enters, exile another target nonland permanent.
When Oblivion Ring leaves the battlefield, return the exiled card to the battlefield under its owner's control.

Sphere of the Suns

Sphere of the Suns enters tapped and with three charge counters on it.
{T}, Remove a charge counter from Sphere of the Suns: Add one mana of any color.

Curator's Ward

Enchant permanent
Enchanted permanent has hexproof.
When enchanted permanent leaves the battlefield, if it was historic, draw two cards. (Artifacts, legendaries, and Sagas are historic.)

Temple of the False God

{T}: Add {C}{C}. Activate only if you control five or more lands.

Ethereal Valkyrie

Flying
Whenever Ethereal Valkyrie enters or attacks, draw a card, then exile a card from your hand face down. It becomes foretold. Its foretell cost is its mana cost reduced by {2}. (On a later turn, you may cast it for its foretell cost, even if this creature has left the battlefield.)

Encroaching Wastes

{T}: Add {C}.
{4}, {T}, Sacrifice Encroaching Wastes: Destroy target nonbasic land.

Military Intelligence

Whenever you attack with two or more creatures, draw a card.

Azorius Chancery

Azorius Chancery enters tapped.
When Azorius Chancery enters, return a land you control to its owner's hand.
{T}: Add {W}{U}.

Delusions of Mediocrity

When Delusions of Mediocrity enters, you gain 10 life.
When Delusions of Mediocrity leaves the battlefield, you lose 10 life.

Pentad Prism

Sunburst (This enters with a charge counter on it for each color of mana spent to cast it.)
Remove a charge counter from Pentad Prism: Add one mana of any color.

Gift of Estates

If an opponent controls more lands than you, search your library for up to three Plains cards, reveal them, put them into your hand, then shuffle.

Reconnaissance Mission

Whenever a creature you control deals combat damage to a player, you may draw a card.
Cycling {2} ({2}, Discard this card: Draw a card.)

Warden of Evos Isle

Flying
Creature spells with flying you cast cost {1} less to cast.

Arcane Denial

Counter target spell. Its controller may draw up to two cards at the beginning of the next turn's upkeep.
You draw a card at the beginning of the next turn's upkeep.

Remorseful Cleric

Flying
Sacrifice Remorseful Cleric: Exile target player's graveyard.

Dream Trawler

Flying, lifelink
Whenever you draw a card, Dream Trawler gets +1/+0 until end of turn.
Whenever Dream Trawler attacks, draw a card.
Discard a card: Dream Trawler gains hexproof until end of turn. Tap it.

Retraction Helix

Spectral Sailor

Flash (You may cast this spell any time you could cast an instant.)
Flying
{3}{U}: Draw a card.

Skycat Sovereign

Flying
Skycat Sovereign gets +1/+1 for each other creature you control with flying.
{2}{W}{U}: Create a 1/1 white Cat Bird creature token with flying.

Akroan Horse

Defender
When Akroan Horse enters, an opponent gains control of it.
At the beginning of your upkeep, each opponent creates a 1/1 white Soldier creature token.

Exotic Orchard

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

Siren Stormtamer

Flying
{U}, Sacrifice Siren Stormtamer: Counter target spell or ability that targets you or a creature you control.

Lich's Tomb

You don't lose the game for having 0 or less life.
Whenever you lose life, sacrifice a permanent for each 1 life you lost. (Damage causes loss of life.)

Robe of Mirrors

Enchant creature (Target a creature as you cast this. This card enters attached to that creature.)
Enchanted creature has shroud. (It can't be the target of spells or abilities.)

Steel-Plume Marshal

Flying
Whenever Steel-Plume Marshal attacks, other attacking creatures you control with flying get +2/+2 until end of turn.

Mulldrifter

Flying
When Mulldrifter enters, draw two cards.
Evoke {2}{U} (You may cast this spell for its evoke cost. If you do, it's sacrificed when it enters.)

Imprisoned in the Moon

Enchant creature, land, or planeswalker
Enchanted permanent is a colorless land with "{T}: Add {C}" and loses all other card types and abilities.

Lapse of Certainty

Counter target spell. If that spell is countered this way, put it on top of its owner's library instead of into that player's graveyard.

Windreader Sphinx

Flying
Whenever a creature with flying attacks, you may draw a card.

Inniaz, the Gale Force

Flying
{2}{W/U}: Attacking creatures with flying get +1/+1 until end of turn. ({W/U} can be paid with either {W} or {U}.)
Whenever three or more creatures you control with flying attack, each player gains control of a nonland permanent of your choice controlled by the player to their right.

Temple of Enlightenment

Temple of Enlightenment enters tapped.
When Temple of Enlightenment enters, scry 1.
{T}: Add {W} or {U}.

Jubilant Skybonder

Flying
Creatures you control with flying have "Spells your opponents cast that target this creature cost {2} more to cast."

Time Wipe

Return a creature you control to its owner's hand, then destroy all creatures.

Empyrean Eagle

Flying
Other creatures you control with flying get +1/+1.

Nimble Obstructionist

Flash
Flying
Cycling {2}{U} ({2}{U}, Discard this card: Draw a card.)
When you cycle Nimble Obstructionist, counter target activated or triggered ability you don't control.

Nimbus Maze

{T}: Add {C}.
{T}: Add {W}. Activate only if you control an Island.
{T}: Add {U}. Activate only if you control a Plains.

Command Tower

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

Battle Screech

Create two 1/1 white Bird creature tokens with flying.
Flashback—Tap three untapped white creatures you control. (You may cast this card from your graveyard for its flashback cost. Then exile it.)

Cleansing Nova

Choose one —
• Destroy all creatures.
• Destroy all artifacts and enchantments.

Battlefield Raptor

Migratory Route

Create four 1/1 white Bird creature tokens with flying.
Basic landcycling {2} ({2}, Discard this card: Search your library for a basic land card, reveal it, put it into your hand, then shuffle.)

Storm Herd

Create X 1/1 white Pegasus creature tokens with flying, where X is your life total.

Timely Ward

You may cast Timely Ward as though it had flash if it targets a commander.
Enchant creature
Enchanted creature has indestructible.

Favorable Winds

Creatures you control with flying get +1/+1.

Thought Devourer

Flying
Your maximum hand size is reduced by four.

Kangee's Lieutenant

Flying
Whenever Kangee's Lieutenant attacks, attacking creatures with flying get +1/+1 until end of turn.
Encore {5}{W} ({5}{W}, Exile this card from your graveyard: For each opponent, create a token copy that attacks that opponent this turn if able. They gain haste. Sacrifice them at the beginning of the next end step. Activate only as a sorcery.)