Mindshrieker

Flying
{2}: Target player mills a card. Mindshrieker gets +X/+X until end of turn, where X is the milled card's mana value.

Somberwald Sage

{T}: Add three mana of any one color. Spend this mana only to cast creature spells.

Aerie Mystics

Flying
{1}{G}{U}: Creatures you control gain shroud until end of turn. (They can't be the targets of spells or abilities.)

Augury Owl

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

Tidehollow Strix

Flying
Deathtouch (Any amount of damage this deals to a creature is enough to destroy it.)

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.)

Palace Familiar

Flying
When Palace Familiar dies, draw a card.

Galvanic Alchemist

Soulbond (You may pair this creature with another unpaired creature when either enters. They remain paired for as long as you control both of them.)
As long as Galvanic Alchemist is paired with another creature, each of those creatures has "{2}{U}: Untap this creature."

Warden of Evos Isle

Flying
Creature spells with flying you cast cost {1} less to cast.

Necropolis

Defender (This creature can't attack.)
Exile a creature card from your graveyard: Put X +0/+1 counters on Necropolis, where X is the exiled card's mana value.

Owl Familiar

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

Traumatic Visions

Counter target spell.
Basic landcycling {1}{U} ({1}{U}, Discard this card: Search your library for a basic land card, reveal it, put it into your hand, then shuffle.)

Talon Trooper

Arcanist's Owl

Flying
When Arcanist's Owl enters, look at the top four cards of your library. You may reveal an artifact or enchantment card from among them and put it into your hand. Put the rest on the bottom of your library in a random order.

Blizzard Strix

Flash
Flying
When Blizzard Strix enters, if you control another snow permanent, exile target permanent other than Blizzard Strix. Return that card to the battlefield under its owner's control at the beginning of the next end step.

Jötun Owl Keeper

Cumulative upkeep {W} or {U} (At the beginning of your upkeep, put an age counter on this permanent, then sacrifice it unless you pay its upkeep cost for each age counter on it.)
When Jötun Owl Keeper dies, create a 1/1 white Bird creature token with flying for each age counter on it.

Stormscape Familiar

Flying
White spells and black spells you cast cost {1} less to cast.

Judge's Familiar

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

Stunted Growth

Target player chooses three cards from their hand and puts them on top of their library in any order.

Sage Owl

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

Ebony Owl Netsuke

At the beginning of each opponent's upkeep, if that player has seven or more cards in hand, Ebony Owl Netsuke deals 4 damage to that player.

Sky Theater Strix

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

Deadfall

Creatures with forestwalk can be blocked as though they didn't have forestwalk.

Vega, the Watcher

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

Spire Owl

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

Parasitic Strix

Flying
When Parasitic Strix enters, if you control a black permanent, target player loses 2 life and you gain 2 life.

Senate Courier

Flying
{1}{W}: Senate Courier gains vigilance until end of turn.

Tempest Owl

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

Esior, Wardwing Familiar

Flying
Spells your opponents cast that target one or more commanders you control cost {3} more to cast.
Partner (You can have two commanders if both have partner.)

Jhoira's Familiar

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

Thaumaturge's Familiar

Flying
When Thaumaturge's Familiar enters, scry 1.

Chromatic Lantern

Lands you control have "{T}: Add one mana of any color."
{T}: Add one mana of any color.

Wing Shards

Target player sacrifices an attacking creature of their choice.
Storm (When you cast this spell, copy it for each spell cast before it this turn. You may choose new targets for the copies.)

Baleful Strix

Flying, deathtouch
When Baleful Strix enters, draw a card.

Touch of Brilliance

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.

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.

Whiteout

All creatures lose flying until end of turn.
Sacrifice a snow land: Return Whiteout from your graveyard to your hand.

Crookclaw Elder

Flying
Tap two untapped Birds you control: Draw a card.
Tap two untapped Wizards you control: Target creature gains flying until end of turn.

Gather Specimens

If a creature would enter the battlefield under an opponent's control this turn, it enters under your control instead.

Fable of Wolf and Owl

Whenever you cast a green spell, you may create a 2/2 green Wolf creature token.
Whenever you cast a blue spell, you may create a 1/1 blue Bird creature token with flying.