Kindred Discovery

As Kindred Discovery enters the battlefield, choose a creature type.
Whenever a creature you control of the chosen type enters the battlefield or attacks, draw a card.

Messenger Jays

Flying
Council's dilemma — When Messenger Jays enters the battlefield, starting with you, each player votes for feather or quill. Put a +1/+1 counter on Messenger Jays for each feather vote and draw a card for each quill vote. For each card drawn this way, discard a card.

Mu Yanling, Celestial Wind

+1: Until your next turn, up to one target creature gets -5/-0.
−3: Return up to two target creatures to their owners' hands.
−7: Creatures you control with flying get +5/+5 until end of turn.

Donal, Herald of Wings

Whenever you cast a nonlegendary creature spell with flying, you may copy it, except the copy is a 1/1 Spirit in addition to its other types. Do this only once each turn. (The copy becomes a token.)

Koilos Roc

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

Tempest Owl

Kicker {4}{U} (You may pay an additional {4}{U} as you cast this spell.)
Flying
When Tempest Owl enters the battlefield, if it was kicked, tap up to three target permanents.

Snow-Covered Island

Meneldor, Swift Savior

Flying
Whenever Meneldor, Swift Savior deals combat damage to a player, exile up to one target creature you own, then return it to the battlefield under your control.

Ringwarden Owl

Flying (This creature can't be blocked except by creatures with flying or reach.)
Prowess (Whenever you cast a noncreature spell, this creature gets +1/+1 until end of turn.)

Kingfisher

Flying
When Kingfisher dies, draw a card.

Giant Albatross

Flying
When Giant Albatross dies, you may pay {1}{U}. If you do, for each creature that dealt damage to Giant Albatross this turn, destroy that creature unless its controller pays 2 life. A creature destroyed this way can't be regenerated.

Mist Raven

Flying
When Mist Raven enters the battlefield, return target creature to its owner's hand.

Ithilien Kingfisher

Flying
When Ithilien Kingfisher dies, draw a card.

Souvenir Snatcher

Mutate {5}{U} (If you cast this spell for its mutate cost, put it over or under target non-Human creature you own. They mutate into the creature on top plus all abilities from under it.)
Flying
Whenever this creature mutates, gain control of target noncreature artifact.

Glint-Nest Crane

Flying
When Glint-Nest Crane enters the battlefield, look at the top four cards of your library. You may reveal an artifact card from among them and put it into your hand. Put the rest on the bottom of your library in any order.

Swan Song

Counter target enchantment, instant, or sorcery spell. Its controller creates a 2/2 blue Bird creature token with flying.

Owl Familiar

Flying
When Owl Familiar enters the battlefield, draw a card, then discard a card.

Cloudfin Raptor

Flying
Evolve (Whenever a creature enters the battlefield under your control, if that creature has greater power or toughness than this creature, put a +1/+1 counter on this creature.)

Silver Raven

Flying
When Silver Raven enters the battlefield, scry 1. (Look at the top card of your library. You may put that card on the bottom of your library.)

Rimefeather Owl

Flying
Rimefeather Owl's power and toughness are each equal to the number of snow permanents on the battlefield.
{1}{S}: Put an ice counter on target permanent.
Permanents with ice counters on them are snow.

Raven Familiar

Flying
Echo {2}{U} (At the beginning of your upkeep, if this came under your control since the beginning of your last upkeep, sacrifice it unless you pay its echo cost.)
When Raven Familiar enters the battlefield, look at the top three cards of your library. Put one of them into your hand and the rest on the bottom of your library in any order.

Umara Raptor

Flying
Whenever Umara Raptor or another Ally enters the battlefield under your control, you may put a +1/+1 counter on Umara Raptor.

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.)

Sky Theater Strix

Flying
Whenever you cast a noncreature spell, Sky Theater Strix gets +1/+0 until end of turn.

Pilfering Hawk

Flying
{S}, {T}: Draw a card, then discard a card. ({S} can be paid with one mana from a snow source.)

Rishadan Brigand

Flying
When Rishadan Brigand enters the battlefield, each opponent sacrifices a permanent unless they pay {3}.
Rishadan Brigand can block only creatures with flying.

Runewing

Kefnet's Monument

Blue creature spells you cast cost {1} less to cast.
Whenever you cast a creature spell, target creature an opponent controls doesn't untap during its controller's next untap step.

Foul Watcher

Flying
When Foul Watcher enters the battlefield, surveil 1. (Look at the top card of your library. You may put that card into your graveyard.)
Delirium — Foul Watcher gets +1/+0 as long as there are four or more card types among cards in your graveyard.

Celestial Messenger

Flash (You may cast this card any time you could cast an instant.)
Flying
Celestial Messenger gets +1/+1 as long as you control a Yanling planeswalker.

Palace Familiar

Flying
When Palace Familiar dies, draw a card.

Augury Owl

Flying
When Augury Owl enters the battlefield, scry 3. (Look at the top three cards of your library, then put any number of them on the bottom of your library and the rest on top in any order.)

Sanctuary Raptor

Flying
Whenever Sanctuary Raptor attacks, if you control three or more tokens, Sanctuary Raptor gets +2/+0 and gains first strike until end of turn.

Coveted Peacock

Flying
Whenever Coveted Peacock attacks, you may goad target creature defending player controls. (Until your next turn, that creature attacks each combat if able and attacks a player other than you if able.)

Sage Owl

Flying
When Sage Owl enters the battlefield, look at the top four cards of your library, then put them back in any order.

Yanling's Harbinger

Flying
When Yanling's Harbinger enters the battlefield, you may search your library and/or graveyard for a card named Mu Yanling, Celestial Wind, reveal it, and put it into your hand. If you search your library this way, shuffle.

Thieving Magpie

Flying (This creature can't be blocked except by creatures with flying or reach.)
Whenever Thieving Magpie deals damage to an opponent, draw a card.