Mesa Unicorn

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

Neighborhood Guardian

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

Ephemerate

Exile target creature you control, then return it to the battlefield under its owner's control.
Rebound (If you cast this spell from your hand, exile it as it resolves. At the beginning of your next upkeep, you may cast this card from exile without paying its mana cost.)

Ronom Unicorn

Sacrifice this creature: Destroy target enchantment.

Daybreak Charger

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

Inspiring Unicorn

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

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

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.

Thriving Heath

This land enters tapped. As it enters, choose a color other than white.
{T}: Add {W} or one mana of the chosen color.

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}.)

Blessed Sanctuary

Prevent all noncombat damage that would be dealt to you and creatures you control.
Whenever a nontoken creature you control enters, create a 2/2 white Unicorn creature token.

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.

Plains

Brightmare

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