Concerted Effort

At the beginning of each upkeep, creatures you control gain flying until end of turn if a creature you control has flying. The same is true for fear, first strike, double strike, landwalk, protection, trample, and vigilance.

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.

Aven Gagglemaster

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

Dragonstalker

Rally the Ranks

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

Emeria Angel

Flying
Landfall — Whenever a land you control enters, you may create a 1/1 white Bird creature token with flying.

Healer's Flock

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.)

Shared Triumph

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

Aven Tactician

Flying
When Aven Tactician enters, bolster 1. (Choose a creature with the least toughness among creatures you control and put a +1/+1 counter on it.)

Teshar, Ancestor's Apostle

Flying
Whenever you cast a historic spell, return target creature card with mana value 3 or less from your graveyard to the battlefield. (Artifacts, legendaries, and Sagas are historic.)

Courier Hawk

High Sentinels of Arashin

Flying
High Sentinels of Arashin gets +1/+1 for each other creature you control with a +1/+1 counter on it.
{3}{W}: Put a +1/+1 counter on target creature.

Disenchant

Aerie Auxiliary

Flying
When Aerie Auxiliary enters, support 2. (Put a +1/+1 counter on each of up to two other target creatures.)

Aven Sunstriker

Flying
Double strike (This creature deals both first-strike and regular combat damage.)
Megamorph {4}{W} (You may cast this card face down as a 2/2 creature for {3}. Turn it face up any time for its megamorph cost and put a +1/+1 counter on it.)

Commander Eesha

Freewind Falcon

Aven Cloudchaser

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

Return to Dust

Exile target artifact or enchantment. If you cast this spell during your main phase, you may exile up to one other target artifact or enchantment.

Aven of Enduring Hope

Flying
When Aven of Enduring Hope enters, you gain 3 life.

Rustwing Falcon

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.

Battlefield Raptor

Murmuration

Birds you control get +1/+1 and have vigilance.
At the beginning of your end step, for each spell you've cast this turn, create a 1/2 blue Bird creature token with flying named Storm Crow.

Aven Flock

Flying (This creature can't be blocked except by creatures with flying or reach.)
{W}: Aven Flock gets +0/+1 until end of turn.

Honor of the Pure

Holy Day

Prevent all combat damage that would be dealt this turn.

Aven Skirmisher

Duskrider Falcon

Aven Brigadier

Flying
Other Bird creatures get +1/+1.
Other Soldier creatures get +1/+1.

Aven Liberator

Flying
Morph {3}{W} (You may cast this card face down as a 2/2 creature for {3}. Turn it face up any time for its morph cost.)
When Aven Liberator is turned face up, target creature you control gains protection from the color of your choice until end of turn.

Rally of Wings

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

Gustcloak Savior

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

Soulcatcher

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

Heron of Hope

Flying
If you would gain life, you gain that much life plus 1 instead.
{1}{W}: Heron of Hope gains lifelink until end of turn.

Dauntless Aven

Flying
Whenever Dauntless Aven attacks, untap target creature you control.

Gustcloak Harrier

Flying
Whenever Gustcloak Harrier becomes blocked, you may untap it and remove it from combat.

Steel-Plume Marshal

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

Shrike Force

Magus of the Moat

Aven Mindcensor

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

Spectra Ward

Enchant creature
Enchanted creature gets +2/+2 and has protection from each color. This effect doesn't remove Auras. (It can't be blocked, targeted, or dealt damage by anything that's white, blue, black, red, or green.)

Keen-Eyed Raven

Flying (This creature can't be blocked except by creatures with flying or reach.)
When Keen-Eyed Raven enters, put a +1/+1 counter on another target creature you control.