Cave of the Frost Dragon

If you control two or more other lands, Cave of the Frost Dragon enters tapped.
{T}: Add {W}.
{4}{W}: Cave of the Frost Dragon becomes a 3/4 white Dragon creature with flying until end of turn. It's still a land.

Hakka, Whispering Raven

Flying
Whenever Hakka, Whispering Raven deals combat damage to a player, return it to its owner's hand, then scry 2.

Alrund, God of the Cosmos

Alrund gets +1/+1 for each card in your hand and each foretold card you own in exile.
At the beginning of your end step, choose a card type, then reveal the top two cards of your library. Put all cards of the chosen type revealed this way into your hand and the rest on the bottom of your library in any order.

Alrund, God of the Cosmos // Hakka, Whispering Raven

Winged Words

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

Celestial Regulator

Flying
When Celestial Regulator enters, choose target creature you don't control and tap it. If you control a creature with a counter on it, the chosen creature doesn't untap during its controller's next untap step.

Aven Gagglemaster

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

Angelic Wall

Defender (This creature can't attack.)
Flying

Ambush Paratrooper

Flash
Flying
{5}: Creatures you control get +1/+1 until end of turn.

Aerial Assault

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

Augury Raven

Flying
Foretell {1}{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.)

Cerulean Drake

Flying
Protection from red (This creature can't be blocked, targeted, dealt damage, enchanted, or equipped by anything red.)
Sacrifice Cerulean Drake: Counter target spell that targets you.