Soulcatchers' Aerie

Whenever a Bird is put into your graveyard from the battlefield, put a feather counter on Soulcatchers' Aerie.
Bird creatures get +1/+1 for each feather counter on Soulcatchers' Aerie.

Essence Scatter

Aven Skirmisher

Gustcloak Savior

Flying
Whenever a creature you control becomes blocked, you may untap that creature and remove it from combat.

Icon of Ancestry

As Icon of Ancestry enters, choose a creature type.
Creatures you control of the chosen type get +1/+1.
{3}, {T}: Look at the top three cards of your library. You may reveal a creature card of the chosen type from among them and put it into your hand. Put the rest on the bottom of your library in a random order.

Stormscape Familiar

Flying
White spells and black spells you cast cost {1} less to cast.

Swan Song

Counter target enchantment, instant, or sorcery spell. Its controller creates a 2/2 blue Bird creature token with flying.

Favorable Winds

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

Sage Owl

Flying
When Sage Owl enters, look at the top four cards of your library, then put them back in any order.

Ordered Migration

Domain — Create a 1/1 blue Bird creature token with flying for each basic land type among lands you control.

Terramorphic Expanse

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

Radiant Destiny

Ascend (If you control ten or more permanents, you get the city's blessing for the rest of the game.)
As Radiant Destiny enters, choose a creature type.
Creatures you control of the chosen type get +1/+1. As long as you have the city's blessing, they also have vigilance.

Sol Ring

Aven Gagglemaster

Flying
When Aven Gagglemaster enters, you gain 2 life for each creature you control with flying.

Silver Raven

Flying
When Silver Raven enters, scry 1. (Look at the top card of your library. You may put that card on the bottom.)

Aven Envoy

Plains

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.)

Esior, Wardwing Familiar

Flying
Spells your opponents cast that target one or more commanders you control cost {3} more to cast.
Partner (You can have two commanders if both have partner.)

Wingmate Roc

Flying
Raid — When Wingmate Roc enters, if you attacked this turn, create a 3/4 white Bird creature token with flying.
Whenever Wingmate Roc attacks, you gain 1 life for each attacking creature.

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.)

Crookclaw Elder

Flying
Tap two untapped Birds you control: Draw a card.
Tap two untapped Wizards you control: Target creature gains flying until end of turn.

Rally of Wings

Untap all creatures you control. Creatures you control with flying get +2/+2 until end of turn.

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.

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.)

Coordinated Barrage

Choose a creature type. Coordinated Barrage deals damage to target attacking or blocking creature equal to the number of permanents you control of the chosen type.

Mu Yanling, Sky Dancer

+2: Until your next turn, up to one target creature gets -2/-0 and loses flying.
−3: Create a 4/4 blue Elemental Bird creature token with flying.
−8: You get an emblem with "Islands you control have '{T}: Draw a card.'"

Healer's Flock

Ishai, Ojutai Dragonspeaker

Flying
Whenever an opponent casts a spell, put a +1/+1 counter on Ishai, Ojutai Dragonspeaker.
Partner (You can have two commanders if both have partner.)

Ravenform

Exile target artifact or creature. Its controller creates a 1/1 blue Bird creature token with flying.
Foretell {U} (During your turn, you may pay {2} and exile this card from your hand face down. Cast it on a later turn for its foretell cost.)

Obelisk of Urd

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.)
As Obelisk of Urd enters, choose a creature type.
Creatures you control of the chosen type get +2/+2.

Cloudfin Raptor

Flying
Evolve (Whenever a creature you control enters, if that creature has greater power or toughness than this creature, put a +1/+1 counter on this creature.)

Path of Ancestry

Path of Ancestry enters tapped.
{T}: Add one mana of any color in your commander's color identity. When that mana is spent to cast a creature spell that shares a creature type with your commander, scry 1. (Look at the top card of your library. You may put that card on the bottom.)

Winged Words

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

Island

Tome of Legends

Tome of Legends enters with a page counter on it.
Whenever your commander enters or attacks, put a page counter on Tome of Legends.
{1}, {T}, Remove a page counter from Tome of Legends: Draw a card.

Spire Owl

Flying
When Spire Owl enters, look at the top four cards of your library, then put them back in any order.

Animal Sanctuary

{T}: Add {C}.
{2}, {T}: Put a +1/+1 counter on target Bird, Cat, Dog, Goat, Ox, or Snake.

Crystal Spray

Change the text of target spell or permanent by replacing all instances of one color word with another or one basic land type with another until end of turn.
Draw a card.

Windbrisk Raptor

Flying
Attacking creatures you control have lifelink.

Evolving Wilds

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

Aerial Assault

Destroy target tapped creature. You gain 1 life for each creature you control with flying.

Unclaimed Territory

As Unclaimed Territory enters, choose a creature type.
{T}: Add {C}.
{T}: Add one mana of any color. Spend this mana only to cast a creature spell of the chosen type.

Soulcatcher

Flying
Whenever a creature with flying dies, put a +1/+1 counter on Soulcatcher.

Healer's Hawk

Flying
Lifelink (Damage dealt by this creature also causes you to gain that much life.)

Serra the Benevolent

+2: Creatures you control with flying get +1/+1 until end of turn.
−3: Create a 4/4 white Angel creature token with flying and vigilance.
−6: You get an emblem with "If you control a creature, damage that would reduce your life total to less than 1 reduces it to 1 instead."

Stoneforge Masterwork

Equipped creature gets +1/+1 for each other creature you control that shares a creature type with it.
Equip {2}

Thrummingbird

Flying
Whenever Thrummingbird deals combat damage to a player, proliferate. (Choose any number of permanents and/or players, then give each another counter of each kind already there.)

Empyrean Eagle

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

Judge's Familiar

Flying
Sacrifice Judge's Familiar: Counter target instant or sorcery spell unless its controller pays {1}.

Crookclaw Transmuter

Flash
Flying
When Crookclaw Transmuter enters, switch target creature's power and toughness until end of turn.

Rally the Ranks

As Rally the Ranks enters, choose a creature type.
Creatures you control of the chosen type get +1/+1.

Veil of Birds

When an opponent casts a spell, if Veil of Birds is an enchantment, Veil of Birds becomes a 1/1 Bird creature with flying.

Herald's Horn

As Herald's Horn enters, choose a creature type.
Creature spells you cast of the chosen type cost {1} less to cast.
At the beginning of your upkeep, look at the top card of your library. If it's a creature card of the chosen type, you may reveal it and put it into your hand.

Thieving Magpie

Flying (This creature can't be blocked except by creatures with flying or reach.)
Whenever Thieving Magpie deals damage to an opponent, draw a card.

Shared Triumph

As Shared Triumph enters, choose a creature type.
Creatures of the chosen type get +1/+1.

Warden of Evos Isle

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

Gravitational Shift

Creatures with flying get +2/+0.
Creatures without flying get -2/-0.

Palace Familiar

Flying
When Palace Familiar dies, draw a card.

Augury Owl

Flying
When Augury Owl enters, scry 3. (Look at the top three cards of your library, then put any number of them on the bottom and the rest on top in any order.)

Vanquisher's Banner

As Vanquisher's Banner enters, choose a creature type.
Creatures you control of the chosen type get +1/+1.
Whenever you cast a creature spell of the chosen type, draw a card.

Secluded Courtyard

As this land enters, choose a creature type.
{T}: Add {C}.
{T}: Add one mana of any color. Spend this mana only to cast a creature spell of the chosen type or activate an ability of a creature source of the chosen type.

Alrund's Epiphany

Create two 1/1 blue Bird creature tokens with flying. Take an extra turn after this one. Exile Alrund's Epiphany.
Foretell {4}{U}{U} (During your turn, you may pay {2} and exile this card from your hand face down. Cast it on a later turn for its foretell cost.)

Lost Vale

(Transforms from Dowsing Dagger.)
{T}: Add three mana of any one color.

Dowsing Dagger

When Dowsing Dagger enters, target opponent creates two 0/2 green Plant creature tokens with defender.
Equipped creature gets +2/+1.
Whenever equipped creature deals combat damage to a player, you may transform Dowsing Dagger.
Equip {2}

Dowsing Dagger // Lost Vale

Serra Aviary

Commander's Sphere

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

Reliquary Tower

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

Cavern of Souls

As Cavern of Souls enters, choose a creature type.
{T}: Add {C}.
{T}: Add one mana of any color. Spend this mana only to cast a creature spell of the chosen type, and that spell can't be countered.

Eyes in the Skies

Create a 1/1 white Bird creature token with flying, then populate. (Create a token that's a copy of a creature token you control.)

Airborne Aid

Draw a card for each Bird on the battlefield.

Apex Hawks

Multikicker {1}{W} (You may pay an additional {1}{W} any number of times as you cast this spell.)
Flying
Apex Hawks enters with a +1/+1 counter on it for each time it was kicked.

Battlefield Raptor

Aven Cloudchaser

Flying (This creature can't be blocked except by creatures with flying or reach.)
When Aven Cloudchaser enters, destroy target enchantment.

Deluge

Dovescape

({W/U} can be paid with either {W} or {U}.)
Whenever a player casts a noncreature spell, counter that spell. That player creates X 1/1 white and blue Bird creature tokens with flying, where X is the spell's mana value.

Door of Destinies

As Door of Destinies enters, choose a creature type.
Whenever you cast a spell of the chosen type, put a charge counter on Door of Destinies.
Creatures you control of the chosen type get +1/+1 for each charge counter on Door of Destinies.

Smothering Tithe

Whenever an opponent draws a card, that player may pay {2}. If the player doesn't, you create a Treasure token. (It's an artifact with "{T}, Sacrifice this artifact: Add one mana of any color.")