Inspiring Unicorn

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

Plains

Concordia Pegasus

Moment of Triumph

Target creature gets +2/+2 until end of turn. You gain 2 life.

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.

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.

Brightmare

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

Archon of Sun's Grace

Flying
Lifelink (Damage dealt by this creature also causes you to gain that much life.)
Pegasus creatures you control have lifelink.
Constellation — Whenever an enchantment you control enters, create a 2/2 white Pegasus creature token with flying.

Armored Ascension

Enchant creature
Enchanted creature gets +1/+1 for each Plains you control and has flying.

It That Rides as One

Lone Rider

First strike, lifelink
At the beginning of the end step, if you gained 3 or more life this turn, transform Lone Rider.

Lone Rider // It That Rides as One

Cathars' Crusade

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

Sungrace Pegasus

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

Sacred Mesa

At the beginning of your upkeep, sacrifice Sacred Mesa unless you sacrifice a Pegasus.
{1}{W}: Create a 1/1 white Pegasus creature token with flying.

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.

Mesa Unicorn

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

Outflank

Outflank deals damage to target attacking or blocking creature equal to the number of creatures you control.

Sunbond

Enchant creature
Enchanted creature has "Whenever you gain life, put that many +1/+1 counters on this creature."

Path of Bravery

As long as your life total is greater than or equal to your starting life total, creatures you control get +1/+1.
Whenever one or more creatures you control attack, you gain life equal to the number of attacking creatures.

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.)

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.