Steadfast Unicorn

{3}{W}: Creatures you control get +1/+1 and gain vigilance until end of turn. Activate only during your turn. (Attacking doesn't cause them to tap.)

Thurid, Mare of Destiny

Flying, lifelink
Whenever you cast a Pegasus, Unicorn, or Horse creature spell, copy it. (The copy becomes a token.)
Other Pegasi, Unicorns, and Horses you control get +1/+1.

Inspiring Unicorn

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

Armored Pegasus

Neighborhood Guardian

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

Bill the Pony

When Bill the Pony enters, create two Food tokens. (They're artifacts with "{2}, {T}, Sacrifice this token: You gain 3 life.")
Sacrifice a Food: Until end of turn, target creature you control assigns combat damage equal to its toughness rather than its power.

Loyal Pegasus

Flying
This creature can't attack or block alone.

Mistral Charger

Summon: Ixion

(As this Saga enters and after your draw step, add a lore counter. Sacrifice after III.)
I — Aerospark — Exile target creature an opponent controls until this Saga leaves the battlefield.
II, III — Put a +1/+1 counter on each of up to two target creatures you control. You gain 2 life.
First strike

Mesa Unicorn

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

Ronom Unicorn

Sacrifice this creature: Destroy target enchantment.

Celestial Unicorn

Whenever you gain life, put a +1/+1 counter on this creature.

Keleth, Sunmane Familiar

Whenever a commander you control attacks, put a +1/+1 counter on it.
Partner (You can have two commanders if both have partner.)

Sungrace Pegasus

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

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.

Opaline Unicorn

Crested Sunmare

Other Horses you control have indestructible.
At the beginning of each end step, if you gained life this turn, create a 5/5 white Horse creature token.

Splendor Mare

Lifelink
Cycling {1}{W} ({1}{W}, Discard this card: Draw a card.)
When you cycle this card, put a lifelink counter on target creature you control.

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.