Vryn Wingmare

Flying
Noncreature spells cost {1} more to cast.

Brightmare

When this creature enters, tap up to one target creature. You gain life equal to that creature's power.

Stormfront Pegasus

Captivating Unicorn

Constellation — Whenever an enchantment you control enters, tap target creature an opponent controls.

Mesa Unicorn

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

Sunmane Pegasus

Flying
{1}{W}: This creature gains vigilance and lifelink until end of turn. (Attacking doesn't cause it to tap. Damage dealt by it also causes you to gain that much life.)

Pegasus Courser

Flying
Whenever this creature attacks, another target attacking creature gains flying until end of turn.

Shepherd of the Clouds

Flying, vigilance
When this creature enters, return target permanent card with mana value 3 or less from your graveyard to your hand. Return that card to the battlefield instead if you control a Mount.

Nyxborn Unicorn

Bestow {3}{W} (If you cast this card for its bestow cost, it's an Aura spell with enchant creature. It becomes a creature again if it's not attached.)
Mentor (Whenever this creature attacks, put a +1/+1 counter on target attacking creature with lesser power.)
Enchanted creature gets +2/+2 and has mentor.

Emiel the Blessed

{3}: Exile another target creature you control, then return it to the battlefield under its owner's control.
Whenever another creature you control enters, you may pay {G/W}. If you do, put a +1/+1 counter on it. If it's a Unicorn, put two +1/+1 counters on it instead. ({G/W} can be paid with either {G} or {W}.)

Inspiring Unicorn

Whenever this creature attacks, creatures you control get +1/+1 until end of turn.

Plated Pegasus

Flash (You may cast this spell any time you could cast an instant.)
Flying
If a spell would deal damage to a permanent or player, prevent 1 damage that spell would deal to that permanent or player.

Daybreak Charger

When this creature enters, target creature gets +2/+0 until end of turn.

Valorous Steed

Vigilance (Attacking doesn't cause this creature to tap.)
When this creature enters, create a 2/2 white Knight creature token with vigilance.

Ronom Unicorn

Sacrifice this creature: Destroy target enchantment.

Neighborhood Guardian

Whenever another creature you control with power 2 or less enters, target creature you control gets +1/+1 until end of turn.

Arborea Pegasus

Flying
When this creature enters, target creature gets +1/+1 and gains flying until end of turn.