Harsh Mercy

Each player chooses a creature type. Destroy all creatures that aren't of a type chosen this way. They can't be regenerated.

Eagle of Deliverance

Flying
When Eagle of Deliverance enters the battlefield, put an indestructible counter on another target creature you control. Draw a card if that creature's power is 2 or less.

Path to Exile

Exile target creature. Its controller may search their library for a basic land card, put that card onto the battlefield tapped, then shuffle.

Icon of Ancestry

As Icon of Ancestry enters the battlefield, choose a creature type.
Creatures you control of the chosen type get +1/+1.
{3}, {T}: Look at the top three cards of your library. You may reveal a creature card of the chosen type from among them and put it into your hand. Put the rest on the bottom of your library in a random order.

Cloudchaser Kestrel

Flying
When Cloudchaser Kestrel enters the battlefield, destroy target enchantment.
{W}: Target permanent becomes white until end of turn.

Serra Aviary

Swords to Plowshares

Exile target creature. Its controller gains life equal to its power.

Soulcatcher

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

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.

Ravnica at War

Rally of Wings

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

Freewind Falcon

Unbreakable Formation

Creatures you control gain indestructible until end of turn.
Addendum — If you cast this spell during your main phase, put a +1/+1 counter on each of those creatures and they gain vigilance until end of turn.

Rustwing Falcon

Cut a Deal

Each opponent draws a card, then you draw a card for each opponent who drew a card this way.

Healer's Flock

Gwaihir, Greatest of the Eagles

Flying
Whenever Gwaihir attacks, target attacking creature gains flying until end of turn.
At the beginning of each end step, if you gained 3 or more life this turn, create a 3/3 white Bird creature token with flying and "Whenever this creature attacks, target attacking creature gains flying until end of turn."

Soraya the Falconer

Bird creatures get +1/+1.
{1}{W}: Target Bird creature gains banding until end of turn. (Any creatures with banding, and up to one without, can attack in a band. Bands are blocked as a group. If any creatures with banding a player controls are blocking or being blocked by a creature, that player divides that creature's combat damage, not its controller, among any of the creatures it's being blocked by or is blocking.)

Mass Calcify

Cathars' Crusade

Whenever a creature enters the battlefield under your control, put a +1/+1 counter on each creature you control.

Idyllic Grange

({T}: Add {W}.)
Idyllic Grange enters the battlefield tapped unless you control three or more other Plains.
When Idyllic Grange enters the battlefield untapped, put a +1/+1 counter on target creature you control.

Aerial Assault

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

Cloudchaser Eagle

Flying
When Cloudchaser Eagle enters the battlefield, destroy target enchantment.

Wing Shards

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

Eyes in the Skies

Create a 1/1 white Bird creature token with flying, then populate. (Create a token that's a copy of a creature token you control.)

Courier Hawk

Secret Rendezvous

You and target opponent each draw three cards.

Rally the Ranks

As Rally the Ranks enters the battlefield, choose a creature type.
Creatures you control of the chosen type get +1/+1.

Duskrider Peregrine

Flying, protection from black
Suspend 3—{1}{W} (Rather than cast this card from your hand, you may pay {1}{W} and exile it with three time counters on it. At the beginning of your upkeep, remove a time counter. When the last is removed, you may cast it without paying its mana cost. It has haste.)

Nesting Dovehawk

Flying
At the beginning of combat on your turn, populate. (Create a token that's a copy of a creature token you control.)
Whenever a creature token enters the battlefield under your control, put a +1/+1 counter on Nesting Dovehawk.

Steel-Plume Marshal

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

Battlefield Raptor

Healer's Hawk

Formation

Target creature gains banding until end of turn. (Any creatures with banding, and up to one without, can attack in a band. Bands are blocked as a group. If any creatures with banding a player controls are blocking or being blocked by a creature, that player divides that creature's combat damage, not its controller, among any of the creatures it's being blocked by or is blocking.)
Draw a card at the beginning of the next turn's upkeep.

Always Watching

Nontoken creatures you control get +1/+1 and have vigilance.

Paladin Class

(Gain the next level as a sorcery to add its ability.)
Spells your opponents cast during your turn cost {1} more to cast.
{2}{W}: Level 2
Creatures you control get +1/+1.
{4}{W}: Level 3
Whenever you attack, until end of turn, target attacking creature gets +1/+1 for each other attacking creature and gains double strike.

Aven Brigadier

Flying
Other Bird creatures get +1/+1.
Other Soldier creatures get +1/+1.

Wings of the Guard

Flying
Melee (Whenever this creature attacks, it gets +1/+1 until end of turn for each opponent you attacked this combat.)

Eagles of the North

Flying
When Eagles of the North enters the battlefield, creatures you control get +1/+0 and gain first strike until end of turn.
Plainscycling {1} ({1}, Discard this card: Search your library for a Plains card, reveal it, put it into your hand, then shuffle.)

Duskrider Falcon

Mind's Eye

Whenever an opponent draws a card, you may pay {1}. If you do, draw a card.

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.

Glorious Anthem

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.

Honor of the Pure

Roc Egg

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

Ranger's Hawk

Flying
{3}, {T}, Tap another untapped creature you control: Venture into the dungeon. Activate only as a sorcery. (Enter the first room or advance to the next room.)

Wingmate Roc

Flying
Raid — When Wingmate Roc enters the battlefield, if you attacked this turn, create a 3/4 white Bird creature token with flying.
Whenever Wingmate Roc attacks, you gain 1 life for each attacking creature.

Emeria Angel

Flying
Landfall — Whenever a land enters the battlefield under your control, you may create a 1/1 white Bird creature token with flying.

Reprobation

Enchant creature
Enchanted creature loses all abilities and is a Coward creature with base power and toughness 0/1. (It keeps all supertypes but loses all other types and creature types.)

Animal Sanctuary

{T}: Add {C}.
{2}, {T}: Put a +1/+1 counter on target Bird, Cat, Dog, Goat, Ox, or Snake.

Celestial Gatekeeper

Flying
When Celestial Gatekeeper dies, exile it, then return up to two target Bird and/or Cleric permanent cards from your graveyard to the battlefield.

Eagle of the Watch

Cartographer's Hawk

Flying
When Cartographer's Hawk deals combat damage to a player who controls more lands than you, return it to its owner's hand. If you do, you may search your library for a Plains card, put it onto the battlefield tapped, then shuffle.

Phalanx Formation

Strive — This spell costs {1}{W} more to cast for each target beyond the first.
Any number of target creatures each gain double strike until end of turn. (They deal both first-strike and regular combat damage.)