Judge's Familiar

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

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.

Empyrean Eagle

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

Healer's Hawk

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

Pride of the Clouds

Flying
Pride of the Clouds gets +1/+1 for each other creature on the battlefield with flying.
Forecast — {2}{W}{U}, Reveal Pride of the Clouds from your hand: Create a 1/1 white and blue Bird creature token with flying. (Activate only during your upkeep and only once each turn.)

Curious Obsession

Enchant creature
Enchanted creature gets +1/+1 and has "Whenever this creature deals combat damage to a player, you may draw a card."
At the beginning of your end step, if you didn't attack with a creature this turn, sacrifice Curious Obsession.

Vapor Snag

Return target creature to its owner's hand. Its controller loses 1 life.

Plains

Curiosity

Enchant creature
Whenever enchanted creature deals damage to an opponent, you may draw a card.

Skycat Sovereign

Flying
Skycat Sovereign gets +1/+1 for each other creature you control with flying.
{2}{W}{U}: Create a 1/1 white Cat Bird creature token with flying.

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.)