Plains

Tranquil Cove

This land enters tapped.
When this land enters, you gain 1 life.
{T}: Add {W} or {U}.

Judge's Familiar

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

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.)

Rally of Wings

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

Elixir of Immortality

{2}, {T}: You gain 5 life. Shuffle Elixir of Immortality and your graveyard into their owner's library.

Aven Mimeomancer

Flying
At the beginning of your upkeep, you may put a feather counter on target creature. If you do, that creature has base power and toughness 3/1 and has flying for as long as it has a feather counter on it.

Favorable Winds

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

Kangee, Sky Warden

Flying, vigilance
Whenever Kangee, Sky Warden attacks, attacking creatures with flying get +2/+0 until end of turn.
Whenever Kangee blocks, blocking creatures with flying get +0/+2 until end of turn.

Healer's Hawk

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

Airborne Aid

Draw a card for each Bird on the battlefield.

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.

Island

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.

Animal Sanctuary

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

Keeper of the Nine Gales

Flying
{T}, Tap two untapped Birds you control: Return target permanent to its owner's hand.

Kangee, Aerie Keeper

Kicker {X}{2} (You may pay an additional {X}{2} as you cast this spell.)
Flying
When Kangee, Aerie Keeper enters, if it was kicked, put X feather counters on it.
Other Bird creatures get +1/+1 for each feather counter on Kangee, Aerie Keeper.

Steel-Plume Marshal

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

Empyrean Eagle

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

Curiosity Crafter

Flying
You have no maximum hand size.
Whenever a creature token you control deals combat damage to a player, draw a card.