Celestial Unicorn

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

Path to Exile

Exile target creature. Its controller may search their library for a basic land card, put that card onto the battlefield tapped, then shuffle.

Akroan Horse

Defender
When Akroan Horse enters, an opponent gains control of it.
At the beginning of your upkeep, each opponent creates a 1/1 white Soldier creature token.

Daybreak Charger

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

Plains

Inspiring Unicorn

Whenever Inspiring Unicorn attacks, creatures you control get +1/+1 until end of turn.

Valiant Changeling

This spell costs {1} less to cast for each creature type among creatures you control. This effect can't reduce the amount of mana this spell costs by more than {5}.
Changeling (This card is every creature type.)
Double strike

Arborea Pegasus

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

Vanquish the Horde

This spell costs {1} less to cast for each creature on the battlefield.
Destroy all creatures.

Swords to Plowshares

Exile target creature. Its controller gains life equal to its power.

Regal Bunnicorn

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

Pegasus Courser

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

Sol Ring

Shield Mare

Shield Mare can't be blocked by red creatures.
When Shield Mare enters or becomes the target of a spell or ability an opponent controls, you gain 3 life.

Marble Diamond

Marble Diamond enters tapped.
{T}: Add {W}.

Opaline Unicorn

Mesa Unicorn

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

Mistral Charger

Irregular Cohort

Changeling (This card is every creature type.)
When Irregular Cohort enters, create a 2/2 colorless Shapeshifter creature token with changeling.

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.

Generous Gift

Destroy target permanent. Its controller creates a 3/3 green Elephant creature token.

Austere Command

Choose two —
• Destroy all artifacts.
• Destroy all enchantments.
• Destroy all creatures with mana value 3 or less.
• Destroy all creatures with mana value 4 or greater.

Armored Warhorse

Loyal Pegasus

Flying
Loyal Pegasus can't attack or block alone.

Loyal Unicorn

Vigilance
Lieutenant — At the beginning of combat on your turn, if you control your commander, prevent all combat damage that would be dealt to creatures you control this turn. Other creatures you control gain vigilance until end of turn.

Boreas Charger

Flying
When Boreas Charger leaves the battlefield, choose an opponent who controls more lands than you. Search your library for a number of Plains cards equal to the difference, reveal those cards, put one of them onto the battlefield tapped and the rest into your hand, then shuffle.

Brightmare

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

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.

Ronom Unicorn

Sacrifice Ronom Unicorn: Destroy target enchantment.

Hour of Reckoning

Convoke (Your creatures can help cast this spell. Each creature you tap while casting this spell pays for {1} or one mana of that creature's color.)
Destroy all nontoken creatures.

Arcane Signet

{T}: Add one mana of any color in your commander's color identity.

Patchwork Banner

As Patchwork Banner enters, choose a creature type.
Creatures you control of the chosen type get +1/+1.
{T}: Add one mana of any color.

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.)

Fumigate

Destroy all creatures. You gain 1 life for each creature destroyed this way.

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.

Shepherd of the Clouds

Flying, vigilance
When Shepherd of the Clouds 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.

Diamond Mare

As Diamond Mare enters, choose a color.
Whenever you cast a spell of the chosen color, you gain 1 life.

Wrath of God

Destroy all creatures. They can't be regenerated.

Mind Stone

{T}: Add {C}.
{1}, {T}, Sacrifice Mind Stone: Draw a card.

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.

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.

Neighborhood Guardian

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