Curiosity Crafter

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

Arachnoid Adaptation

Target creature gets +2/+2 and gains reach until end of turn. Untap it.

Artificer's Assistant

Flying
Whenever you cast a historic spell, scry 1. (Artifacts, legendaries, and Sagas are historic. To scry 1, look at the top card of your library, then you may put that card on the bottom of your library.)

Aven Fisher

Flying (This creature can't be blocked except by creatures with flying or reach.)
When Aven Fisher dies, you may 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.

Thrummingbird

Flying
Whenever Thrummingbird deals combat damage to a player, proliferate. (Choose any number of permanents and/or players, then give each another counter of each kind already there.)

Nephalia Seakite

Flash (You may cast this spell any time you could cast an instant.)
Flying

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.)

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.")

Birds of Paradise

Kingfisher

Flying
When Kingfisher dies, draw a card.

The Goose Mother

Flying
The Goose Mother enters the battlefield with X +1/+1 counters on it.
When The Goose Mother enters the battlefield, create half X Food tokens, rounded up.
Whenever The Goose Mother attacks, you may sacrifice a Food. If you do, draw a card.

Murder of Crows

Flying
Whenever another creature dies, you may draw a card. If you do, discard a card.

Ithilien Kingfisher

Flying
When Ithilien Kingfisher dies, draw a card.

Mist Raven

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

Runewing

Gilded Goose

Flying
When Gilded Goose enters the battlefield, create a Food token. (It's an artifact with "{2}, {T}, Sacrifice this artifact: You gain 3 life.")
{1}{G}, {T}: Create a Food token.
{T}, Sacrifice a Food: Add one mana of any color.

Neurok Familiar

Flying
When Neurok Familiar enters the battlefield, reveal the top card of your library. If it's an artifact card, put it into your hand. Otherwise, put it into your graveyard.

Screaming Swarm

Flying
Whenever you attack with one or more creatures, target player mills that many cards. (To mill a card, a player puts the top card of their library into their graveyard.)
{2}{U}: Put Screaming Swarm from your graveyard into your library second from the top.

Aim High

Untap target creature. It gets +2/+2 and gains reach until end of turn. (It can block creatures with flying.)

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.

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.

Darba

At the beginning of your upkeep, sacrifice Darba unless you pay {G}{G}.

Mercurial Kite

Flying
Whenever Mercurial Kite deals combat damage to a creature, tap that creature. That creature doesn't untap during its controller's next untap step.

Burst of Strength

Put a +1/+1 counter on target creature and untap it.

River Hoopoe

Flying
{3}{G}{U}: You gain 2 life and draw a card.

Aven Surveyor

Flying
When Aven Surveyor enters the battlefield, choose one —
• Put a +1/+1 counter on Aven Surveyor.
• Return target creature to its owner's hand.

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.)

Skyshroud Condor

Cast this spell only if you've cast another spell this turn.
Flying

Palace Familiar

Flying
When Palace Familiar dies, draw a card.

Owl Familiar

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

Owlbear

Trample
Keen Senses — When Owlbear enters the battlefield, draw a card.

Jhoira's Familiar

Flying
Historic spells you cast cost {1} less to cast. (Artifacts, legendaries, and Sagas are historic.)

Dream Thrush

Flying
{T}: Target land becomes the basic land type of your choice until end of turn.

Echo Inspector

Flying
When Echo Inspector enters the battlefield, it connives. (Draw a card, then discard a card. If you discarded a nonland card, put a +1/+1 counter on this creature.)

Aven Courier

Flying
Whenever Aven Courier attacks, choose a counter on a permanent you control. Put a counter of that kind on target permanent you control if it doesn't have a counter of that kind on it.