Waterkin Shaman

Whenever a creature you control with flying enters, Waterkin Shaman gets +1/+1 until end of turn.

Winged Portent

Cleave {4}{G}{U} (You may cast this spell for its cleave cost. If you do, remove the words in square brackets.)
Draw a card for each creature [with flying] you control.

Tide Skimmer

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

Winged Words

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

Soulcatcher

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

Aerial Assault

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

Aven Gagglemaster

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

Lofty Denial

Counter target spell unless its controller pays {1}. If you control a creature with flying, counter that spell unless its controller pays {4} instead.

Wingspan Mentor

When Wingspan Mentor enters, put a flying counter on target non-Human creature you control.
{2}{U}, {T}: Put a +1/+1 counter on each creature you control with flying.

Warden of Evos Isle

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

Rally of Wings

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

Sprite Noble

Flying
Other creatures you control with flying get +0/+1.
{T}: Other creatures you control with flying get +1/+0 until end of turn.

Empyrean Eagle

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

Favorable Winds

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

Steel-Plume Marshal

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

Firespout

Firespout deals 3 damage to each creature without flying if {R} was spent to cast this spell and 3 damage to each creature with flying if {G} was spent to cast this spell. (Do both if {R}{G} was spent.)

Flame Sweep

Flame Sweep deals 2 damage to each creature except for creatures you control with flying.