Plains

Squadron Hawk

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

Commander Eesha

Welkin Hawk

Flying
When this creature dies, you may search your library for a card named Welkin Hawk, reveal that card, put it into your hand, then shuffle.

Aven Brigadier

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

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.

Healer's Flock

Swords to Plowshares

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

Condemn

Put target attacking creature on the bottom of its owner's library. Its controller gains life equal to its toughness.

Soulcatchers' Aerie

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

Lieutenant Kirtar

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

Ethereal Armor

Enchant creature
Enchanted creature gets +1/+1 for each enchantment you control and has first strike.

Healer's Hawk

Flying
Lifelink (Damage dealt by this creature also causes you to gain that much life.)

Kirtar's Desire

Enchant creature
Enchanted creature can't attack.
Threshold — Enchanted creature can't block as long as there are seven or more cards in your graveyard.

Chastise

Destroy target attacking creature. You gain life equal to its power.

Celestial Gatekeeper

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

Disenchant

Convalescent Care

At the beginning of your upkeep, if you have 5 or less life, you gain 3 life and draw a card.

Soulcatcher

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