Loyal Gyrfalcon

Defender, flying
Whenever you cast a white spell, Loyal Gyrfalcon loses defender until end of turn.

Welkin Guide

Flying
When Welkin Guide enters, target creature gets +2/+2 and gains flying until end of turn.

Judge's Familiar

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

Wild Griffin

Lieutenant Kirtar

Flying
{1}{W}, Sacrifice Lieutenant Kirtar: Exile target attacking creature.

Plains

Unmake

Squadron Hawk

Flying
When Squadron Hawk enters, you may search your library for up to three cards named Squadron Hawk, reveal them, put them into your hand, then shuffle.

Swans of Bryn Argoll

Flying
If a source would deal damage to Swans of Bryn Argoll, prevent that damage. The source's controller draws cards equal to the damage prevented this way.

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.)

Decorated Griffin

Flying
{1}{W}: Prevent the next 1 combat damage that would be dealt to you this turn.

Armillary Sphere

{2}, {T}, Sacrifice Armillary Sphere: Search your library for up to two basic land cards, reveal them, put them into your hand, then shuffle.

Armored Ascension

Enchant creature
Enchanted creature gets +1/+1 for each Plains you control and has flying.

Island

Assault Griffin

Martial Coup

Create X 1/1 white Soldier creature tokens. If X is 5 or more, destroy all other creatures.

Wall of Reverence

Defender, flying
At the beginning of your end step, you may gain life equal to the power of target creature you control.

Aven Trailblazer

Flying
Domain — Aven Trailblazer's toughness is equal to the number of basic land types among lands you control.

Rupture Spire

Rupture Spire enters tapped.
When Rupture Spire enters, sacrifice it unless you pay {1}.
{T}: Add one mana of any color.

Lapse of Certainty

Counter target spell. If that spell is countered this way, put it on top of its owner's library instead of into that player's graveyard.

Endure

Prevent all damage that would be dealt to you and permanents you control this turn.

Mirrorweave

Each other creature becomes a copy of target nonlegendary creature until end of turn.

Thistledown Liege

Flash
Other white creatures you control get +1/+1.
Other blue creatures you control get +1/+1.

Oathsworn Giant

Vigilance
Other creatures you control get +0/+2 and have vigilance.

Mirror-Sigil Sergeant

Trample
At the beginning of your upkeep, if you control a blue permanent, you may create a token that's a copy of Mirror-Sigil Sergeant.

Ordered Migration

Domain — Create a 1/1 blue Bird creature token with flying for each basic land type among lands you control.

Endless Horizons

When Endless Horizons enters, search your library for any number of Plains cards, exile them, then shuffle.
At the beginning of your upkeep, you may put a card you own exiled with Endless Horizons into your hand.