Storm Herd

Create X 1/1 white Pegasus creature tokens with flying, where X is your life total.

Plains

Sephara, Sky's Blade

You may pay {W} and tap four untapped creatures you control with flying rather than pay this spell's mana cost.
Flying, lifelink
Other creatures you control with flying have indestructible. (Damage and effects that say "destroy" don't destroy them.)

Mistral Charger

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.

Pegasus Refuge

{2}, Discard a card: Create a 1/1 white Pegasus creature token with flying.

Sunmane Pegasus

Flying
{1}{W}: This creature 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.)

Phyrexian Pegasus

Flying
Whenever this creature attacks, another target attacking creature without flying gains flying until end of turn.

Rescue the Foal

Exile target creature you control, then return that card to the battlefield under its owner's control. (Then exile this card. You may cast the creature later from exile.)

Pegasus Guardian

Flying
At the beginning of your end step, if a permanent you controlled left the battlefield this turn, create a 1/1 white Pegasus creature token with flying.

Pegasus Guardian // Rescue the Foal

Starnheim Courser

Flying
Artifact and enchantment spells you cast cost {1} less to cast.

Stormfront Pegasus

Cavalry Pegasus

Flying
Whenever this creature attacks, each attacking Human gains flying until end of turn.

Pegasus Courser

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

Sacred Mesa

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

Avian Changeling

Changeling (This card is every creature type.)
Flying

Heliod, God of the Sun

Indestructible
As long as your devotion to white is less than five, Heliod isn't a creature. (Each {W} in the mana costs of permanents you control counts toward your devotion to white.)
Other creatures you control have vigilance.
{2}{W}{W}: Create a 2/1 white Cleric enchantment creature token.

Shepherd of the Clouds

Flying, vigilance
When this creature 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.

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.

Arborea Pegasus

Flying
When this creature 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.)

Swords to Plowshares

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

Vryn Wingmare

Flying
Noncreature spells cost {1} more to cast.

Boreas Charger

Flying
When this creature 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.

Trusted Pegasus

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

Mangara, the Diplomat

Lifelink
Whenever an opponent attacks with creatures, if two or more of those creatures are attacking you and/or planeswalkers you control, draw a card.
Whenever an opponent casts their second spell each turn, draw a card.

Concordia Pegasus

Loyal Pegasus

Flying
This creature can't attack or block alone.

Temple of the False God

{T}: Add {C}{C}. Activate only if you control five or more lands.

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.

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.)

Crovax, Ascendant Hero

Other white creatures get +1/+1.
Nonwhite creatures get -1/-1.
Pay 2 life: Return Crovax to its owner's hand.

Armored Pegasus

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.)