Lofty Denial

Counter target spell unless its controller pays {1}. If you control a creature with flying, counter that spell unless its controller pays {4} instead.

Scouting Hawk

Flying
Keen Sight — When Scouting Hawk enters the battlefield, if an opponent controls more lands than you, search your library for a basic Plains card, put it onto the battlefield tapped, then shuffle.

Judge's Familiar

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

Port Town

As Port Town enters the battlefield, you may reveal a Plains or Island card from your hand. If you don't, Port Town enters the battlefield tapped.
{T}: Add {W} or {U}.

Sephara, Sky's Blade

You may pay {W} and tap four untapped creatures you control with flying rather than pay this spell's mana cost.
Flying, lifelink
Other creatures you control with flying have indestructible. (Damage and effects that say "destroy" don't destroy them.)

Miner's Guidewing

Flying, vigilance
When Miner's Guidewing dies, target creature you control explores. (Reveal the top card of your library. Put that card into your hand if it's a land. Otherwise, put a +1/+1 counter on that creature, then put the card back or put it into your graveyard.)

Gustcloak Savior

Flying
Whenever a creature you control becomes blocked, you may untap that creature and remove it from combat.

Windbrisk Raptor

Flying
Attacking creatures you control have lifelink.

Inexorable Tide

Whenever you cast a spell, proliferate. (Choose any number of permanents and/or players, then give each another counter of each kind already there.)

Arctic Aven

Flying
Arctic Aven gets +1/+1 as long as you control a Plains.
{W}: Arctic Aven gains lifelink until end of turn. (Damage dealt by this creature also causes you to gain that much life.)

Idyllic Tutor

Search your library for an enchantment card, reveal it, put it into your hand, then shuffle.

Skymark Roc

Flying
Whenever Skymark Roc attacks, you may return target creature defending player controls with toughness 2 or less to its owner's hand.

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.)

Aven Wind Guide

Flying, vigilance
Creature tokens you control have flying and vigilance.
Embalm {4}{W}{U} ({4}{W}{U}, Exile this card from your graveyard: Create a token that's a copy of it, except it's a white Zombie Bird Warrior with no mana cost. Embalm only as a sorcery.)

Empyrean Eagle

Flying
Other creatures you control with flying get +1/+1.

Aerial Assault

Destroy target tapped creature. You gain 1 life for each creature you control with flying.

Steel-Plume Marshal

Flying
Whenever Steel-Plume Marshal attacks, other attacking creatures you control with flying get +2/+2 until end of turn.

Ojutai's Command

Choose two —
• Return target creature card with mana value 2 or less from your graveyard to the battlefield.
• You gain 4 life.
• Counter target creature spell.
• Draw a card.

Unbounded Potential

Choose one —
• Put a +1/+1 counter on each of up to two target creatures.
• Proliferate. (Choose any number of permanents and/or players, then give each another counter of each kind already there.)
Entwine {3}{W} (Choose both if you pay the entwine cost.)

Staggering Insight

Enchant creature
Enchanted creature gets +1/+1 and has lifelink and "Whenever this creature deals combat damage to a player, 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.)

Watcher of the Spheres

Flying
Creature spells with flying you cast cost {1} less to cast.
Whenever another creature with flying enters the battlefield under your control, Watcher of the Spheres gets +1/+1 until end of turn.

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.

Keeper of the Nine Gales

Flying
{T}, Tap two untapped Birds you control: Return target permanent to its owner's hand.

Favorable Winds

Creatures you control with flying get +1/+1.

Roc Egg

Defender (This creature can't attack.)
When Roc Egg dies, create a 3/3 white Bird creature token with flying.

Break Ties

Choose one —
• Destroy target artifact.
• Destroy target enchantment.
• Exile target card from a graveyard.
Reinforce 1—{W} ({W}, Discard this card: Put a +1/+1 counter on target creature.)

Palace Familiar

Flying
When Palace Familiar dies, draw a card.

Brainstorm

Draw three cards, then put two cards from your hand on top of your library in any order.

Aven Sunstriker

Flying
Double strike (This creature deals both first-strike and regular combat damage.)
Megamorph {4}{W} (You may cast this card face down as a 2/2 creature for {3}. Turn it face up any time for its megamorph cost and put a +1/+1 counter on it.)

Migratory Route

Create four 1/1 white Bird creature tokens with flying.
Basic landcycling {2} ({2}, Discard this card: Search your library for a basic land card, reveal it, put it into your hand, then shuffle.)

Experimental Augury

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. Proliferate. (Choose any number of permanents and/or players, then give each another counter of each kind already there.)

Plains

Battlefield Raptor

Soulcatchers' Aerie

Whenever a Bird is put into your graveyard from the battlefield, put a feather counter on Soulcatchers' Aerie.
Bird creatures get +1/+1 for each feather counter on Soulcatchers' Aerie.

Collective Effort

Escalate—Tap an untapped creature you control. (Pay this cost for each mode chosen beyond the first.)
Choose one or more —
• Destroy target creature with power 4 or greater.
• Destroy target enchantment.
• Put a +1/+1 counter on each creature target player controls.

Light of Hope

Choose one —
• You gain 4 life.
• Destroy target enchantment.
• Put a +1/+1 counter on target creature.

Seaside Haven

{T}: Add {C}.
{W}{U}, {T}, Sacrifice a Bird: Draw a card.

Rally of Wings

Untap all creatures you control. Creatures you control with flying get +2/+2 until end of turn.

Battle Screech

Create two 1/1 white Bird creature tokens with flying.
Flashback—Tap three untapped white creatures you control. (You may cast this card from your graveyard for its flashback cost. Then exile it.)

Dovin, Grand Arbiter

+1: Until end of turn, whenever a creature you control deals combat damage to a player, put a loyalty counter on Dovin, Grand Arbiter.
−1: Create a 1/1 colorless Thopter artifact creature token with flying. You gain 1 life.
−7: Look at the top ten cards of your library. Put three of them into your hand and the rest on the bottom of your library in a random order.

Soulcatcher

Flying
Whenever a creature with flying dies, put a +1/+1 counter on Soulcatcher.

Reflections of Littjara

As Reflections of Littjara enters the battlefield, choose a creature type.
Whenever you cast a spell of the chosen type, copy that spell. (A copy of a permanent spell becomes a token.)

Island

Island Sanctuary

If you would draw a card during your draw step, instead you may skip that draw. If you do, until your next turn, you can't be attacked except by creatures with flying and/or islandwalk.

Airborne Aid

Draw a card for each Bird on the battlefield.

Enlightened Tutor

Search your library for an artifact or enchantment card, reveal it, then shuffle and put that card on top.

Dawn to Dusk

Choose one or both —
• Return target enchantment card from your graveyard to your hand.
• Destroy target enchantment.

Azorius Charm

Choose one —
• Creatures you control gain lifelink until end of turn.
• Draw a card.
• Put target attacking or blocking creature on top of its owner's library.

Squadron Hawk

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