Drift of Phantasms

Defender (This creature can't attack.)
Flying
Transmute {1}{U}{U} ({1}{U}{U}, Discard this card: Search your library for a card with the same mana value as this card, reveal it, put it into your hand, then shuffle. Transmute only as a sorcery.)

Council of Echoes

Flying
Descend 4 — When Council of Echoes enters, if there are four or more permanent cards in your graveyard, return up to one target nonland permanent other than Council of Echoes to its owner's hand.

Raven Wings

Equipped creature gets +1/+0, has flying, and is a Bird in addition to its other types.
Equip {2} ({2}: Attach to target creature you control. Equip only as a sorcery.)

Jem Lightfoote, Sky Explorer

Flying, vigilance
At the beginning of your end step, if you haven't cast a spell from your hand this turn, draw a card.

Clarion Spirit

Whenever you cast your second spell each turn, create a 1/1 white Spirit creature token with flying.

Vertex Paladin

Flying
Vertex Paladin's power and toughness are each equal to the number of creatures you control.

Invasion of Xerex

(As a Siege enters, choose an opponent to protect it. You and others can attack it. When it's defeated, exile it, then cast it transformed.)
When Invasion of Xerex enters, return up to one target creature to its owner's hand.

Invasion of Xerex // Vertex Paladin

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.

Zephyr Boots

Equipped creature has flying.
Whenever equipped creature deals combat damage to a player, draw a card, then discard a card.
Equip {2} ({2}: Attach to target creature you control. Equip only as a sorcery.)

Meticulous Archive

({T}: Add {W} or {U}.)
Meticulous Archive enters tapped.
When Meticulous Archive enters, surveil 1. (Look at the top card of your library. You may put it into your graveyard.)

Prince Imrahil the Fair

Whenever you draw your second card each turn, create a 1/1 white Human Soldier creature token.

Vega, the Watcher

Flying
Whenever you cast a spell from anywhere other than your hand, draw a card.

Koilos Roc

Flash
Flying
When Koilos Roc enters, create a tapped Powerstone token. (It's an artifact with "{T}: Add {C}. This mana can't be spent to cast a nonartifact spell.")

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.

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.)

Nebelgast Beguiler

Seedpod Squire

Flying
Whenever Seedpod Squire attacks, target creature you control without flying gets +1/+1 until end of turn.

Stonerise Spirit

Flying
{4}, Exile a card from your graveyard: Target creature gains flying until end of turn.

Tocasia's Dig Site

{T}: Add {C}.
{3}, {T}: Surveil 1. (Look at the top card of your library. You may put it into your graveyard.)

Harrier Strix

Flying
When Harrier Strix enters, tap target permanent.
{2}{U}: Draw a card, then discard a card.

Mistwalker

Changeling (This card is every creature type.)
Flying
{1}{U}: Mistwalker gets +1/-1 until end of turn.

Access Tunnel

{T}: Add {C}.
{3}, {T}: Target creature with power 3 or less can't be blocked this turn.

Ravenform

Exile target artifact or creature. Its controller creates a 1/1 blue Bird creature token with flying.
Foretell {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.)

Elspeth's Smite

Elspeth's Smite deals 3 damage to target attacking or blocking creature. If that creature would die this turn, exile it instead.