Spitemare

Whenever Spitemare is dealt damage, it deals that much damage to any target.

Vryn Wingmare

Flying
Noncreature spells cost {1} more to cast.

Lightning Mare

This spell can't be countered.
Lightning Mare can't be blocked by blue creatures.
{1}{R}: Lightning Mare gets +1/+0 until end of turn.

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.

Mesa Pegasus

Flying; banding (Any creatures with banding, and up to one without, can attack in a band. Bands are blocked as a group. If any creatures with banding you control are blocking or being blocked by a creature, you divide that creature's combat damage, not its controller, among any of the creatures it's being blocked by or is blocking.)

Pegasus Charger

Flying (This creature can't be blocked except by creatures with flying or reach.)
First strike (This creature deals combat damage before creatures without first strike.)

Sunmane Pegasus

Flying
{1}{W}: Sunmane Pegasus 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.)

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.

Headless Horseman

Inspiring Unicorn

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

Wavebreak Hippocamp

Whenever you cast your first spell during each opponent's turn, draw a card.

Arborea Pegasus

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

Sungrace Pegasus

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

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.

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.

Workhorse

Workhorse enters with four +1/+1 counters on it.
Remove a +1/+1 counter from Workhorse: Add {C}.

Clockwork Steed

Clockwork Steed enters with four +1/+0 counters on it.
Clockwork Steed can't be blocked by artifact creatures.
At end of combat, if Clockwork Steed attacked or blocked this combat, remove a +1/+0 counter from it.
{X}, {T}: Put up to X +1/+0 counters on Clockwork Steed. This ability can't cause the total number of +1/+0 counters on Clockwork Steed to be greater than four. Activate only during your upkeep.

Princess Twilight Sparkle

Flying
Other Alicorns, Horses, Pegasi, Ponies, and Unicorns you control get +1/+1.
{W}{U}{B}{R}{G}: If you control Applejack, Fluttershy, Pinkie Pie, Rainbow Dash, and Rarity, everypony wins the game.

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.

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.

Pearled Unicorn

Mesa Unicorn

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

Wandermare

Whenever you cast a creature spell that has an Adventure, put a +1/+1 counter on Wandermare. (It doesn't need to have gone on the adventure first.)

Zodiac Horse

Islandwalk (This creature can't be blocked as long as defending player controls an Island.)

Timbermare

Haste
Echo {5}{G} (At the beginning of your upkeep, if this came under your control since the beginning of your last upkeep, sacrifice it unless you pay its echo cost.)
When Timbermare enters, tap all other creatures.

Surge Mare

Surge Mare can't be blocked by green creatures.
Whenever Surge Mare deals damage to an opponent, you may draw a card. If you do, discard a card.
{1}{U}: Surge Mare gets +2/-2 until end of turn.

Stormfront Pegasus

Captivating Unicorn

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

Opaline Unicorn

Plague Mare

Plague Mare can't be blocked by white creatures.
When Plague Mare enters, creatures your opponents control get -1/-1 until end of turn.

Dusk Charger

Ascend (If you control ten or more permanents, you get the city's blessing for the rest of the game.)
Dusk Charger gets +2/+2 as long as you have the city's blessing.

Loyal Pegasus

Flying
Loyal Pegasus can't attack or block alone.

Armored Pegasus

Regal Unicorn

Bronze Horse

Trample
As long as you control another creature, prevent all damage that would be dealt to Bronze Horse by spells that target it.

Adarkar Unicorn

{T}: Add {U} or {C}{U}. Spend this mana only to pay cumulative upkeep costs.

Tarpan

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.

Breaching Hippocamp

Flash (You may cast this spell any time you could cast an instant.)
When Breaching Hippocamp enters, untap another target creature you control.

Wishmonger

{2}: Target creature gains protection from the color of its controller's choice until end of turn. Any player may activate this ability.

Riding the Dilu Horse

Target creature gets +2/+2 and gains horsemanship. (It can't be blocked except by creatures with horsemanship. This effect lasts indefinitely.)

Benevolent Unicorn

If a spell would deal damage to a permanent or player, it deals that much damage minus 1 to that permanent or player instead.

Wispmare

Flying
When Wispmare enters, destroy target enchantment.
Evoke {W} (You may cast this spell for its evoke cost. If you do, it's sacrificed when it enters.)

Zebra Unicorn

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

Thundering Mightmare

Soulbond (You may pair this creature with another unpaired creature when either enters. They remain paired for as long as you control both of them.)
As long as Thundering Mightmare is paired with another creature, each of those creatures has "Whenever an opponent casts a spell, put a +1/+1 counter on this creature."

Good-Fortune Unicorn

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

Brightmare

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

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.

Prized Unicorn

All creatures able to block Prized Unicorn do so.

Armored Warhorse

Trusted Pegasus

Flying (This creature can't be blocked except by creatures with flying or reach.)
Whenever Trusted Pegasus attacks, target attacking creature without flying gains flying until end of turn.

Vine Mare

Hexproof (This creature can't be the target of spells or abilities your opponents control.)
Vine Mare can't be blocked by black creatures.

Ebony Horse

{2}, {T}: Untap target attacking creature you control. Prevent all combat damage that would be dealt to and dealt by that creature this turn.

Pegasus Stampede

Buyback—Sacrifice a land. (You may sacrifice a land in addition to any other costs as you cast this spell. If you do, put this card into your hand as it resolves.)
Create a 1/1 white Pegasus creature token with flying.

Ronom Unicorn

Sacrifice Ronom Unicorn: Destroy target enchantment.

Revered Unicorn

Cumulative upkeep {1} (At the beginning of your upkeep, put an age counter on this permanent, then sacrifice it unless you pay its upkeep cost for each age counter on it.)
When Revered Unicorn leaves the battlefield, you gain life equal to the number of age counters on it.

Thundermare

Haste (This creature can attack and {T} as soon as it comes under your control.)
When Thundermare enters, tap all other creatures.

Diamond Mare

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