Good-Fortune Unicorn

Whenever another creature you control enters, put a +1/+1 counter on that creature.

Valorous Steed

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

Lathiel, the Bounteous Dawn

Lifelink
At the beginning of each end step, if you gained life this turn, distribute up to that many +1/+1 counters among any number of other target creatures.

Splendor Mare

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

Celestial Unicorn

Whenever you gain life, put a +1/+1 counter on Celestial Unicorn.

Capashen Unicorn

{1}{W}, {T}, Sacrifice Capashen Unicorn: Destroy target artifact or enchantment.

Zebra Unicorn

Whenever Zebra Unicorn deals damage, you gain that much life.

Plains

Opaline Unicorn

Regal Bunnicorn

Regal Bunnicorn's power and toughness are each equal to the number of nonland permanents you control.

Forest

Seraphic Steed

First strike, lifelink
Whenever Seraphic Steed attacks while saddled, create a 3/3 white Angel creature token with flying.
Saddle 4 (Tap any number of other creatures you control with total power 4 or more: This Mount becomes saddled until end of turn. Saddle only as a sorcery.)

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}.)