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.

Thunderclap Wyvern

Flash (You may cast this spell any time you could cast an instant.)
Flying
Other creatures you control with flying get +1/+1.

Empyrean Eagle

Flying
Other creatures you control with flying 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.

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.

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.

Jubilant Skybonder

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

Windreader Sphinx

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

Favorable Winds

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

Thistledown Liege

Flash
Other white creatures you control get +1/+1.
Other blue creatures you control get +1/+1.

Magus of the Moat

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.)

Warden of Evos Isle

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

Errant and Giada

Flash
Flying
You may look at the top card of your library any time.
You may cast spells with flash or flying from the top of your library.

Swords to Plowshares

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

Steel-Plume Marshal

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

Gravitational Shift

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

Winged Words

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