Ordeal of Heliod

Enchant creature
Whenever enchanted creature attacks, put a +1/+1 counter on it. Then if it has three or more +1/+1 counters on it, sacrifice Ordeal of Heliod.
When you sacrifice Ordeal of Heliod, you gain 10 life.

Mortal's Ardor

Target creature gets +1/+1 and gains lifelink until end of turn. (Damage dealt by the creature also causes its controller to gain that much life.)

Rally for the Throne

Create two 1/1 white Human creature tokens.
Adamant — If at least three white mana was spent to cast this spell, you gain 1 life for each creature you control.

Wingsteed Rider

Flying
Heroic — Whenever you cast a spell that targets Wingsteed Rider, put a +1/+1 counter on Wingsteed Rider.

Castle Ardenvale

Castle Ardenvale enters tapped unless you control a Plains.
{T}: Add {W}.
{2}{W}{W}, {T}: Create a 1/1 white Human creature token.

Rider in Need

Create a 2/2 white Knight creature token with vigilance. (Then exile this card. You may cast the creature later from exile.)

Lonesome Unicorn

Lonesome Unicorn // Rider in Need

Favored Hoplite

Heroic — Whenever you cast a spell that targets Favored Hoplite, put a +1/+1 counter on Favored Hoplite and prevent all damage that would be dealt to it this turn.

Chosen by Heliod

Enchant creature
When Chosen by Heliod enters, draw a card.
Enchanted creature gets +0/+2.

Akroan Skyguard

Flying
Heroic — Whenever you cast a spell that targets Akroan Skyguard, put a +1/+1 counter on Akroan Skyguard.

Plains

Hold at Bay

Prevent the next 7 damage that would be dealt to any target this turn.

Dizzying Swoop

Tap up to two target creatures. (Then exile this card. You may cast the creature later from exile.)

Ardenvale Tactician

Ardenvale Tactician // Dizzying Swoop

Staff of the Sun Magus

Whenever you cast a white spell or a Plains you control enters, you gain 1 life.

Beloved Princess

Lifelink
Beloved Princess can't be blocked by creatures with power 3 or greater.

On Alert

Target creature gets +2/+2 until end of turn. Untap it. (Then exile this card. You may cast the creature later from exile.)

Silverflame Squire

Silverflame Squire // On Alert

Divine Favor

Enchant creature
When Divine Favor enters, you gain 3 life.
Enchanted creature gets +1/+3.

Silverflame Ritual

Put a +1/+1 counter on each creature you control.
Adamant — If at least three white mana was spent to cast this spell, creatures you control gain vigilance until end of turn.

Acolyte's Reward

Prevent the next X damage that would be dealt to target creature this turn, where X is your devotion to white. If damage is prevented this way, Acolyte's Reward deals that much damage to any target. (Each {W} in the mana costs of permanents you control counts toward your devotion to white.)

Pay No Heed

Prevent all damage a source of your choice would deal this turn.

Felidar Sovereign

Vigilance (Attacking doesn't cause this creature to tap.)
Lifelink (Damage dealt by this creature also causes you to gain that much life.)
At the beginning of your upkeep, if you have 40 or more life, you win the game.

Linden, the Steadfast Queen

Vigilance (Attacking doesn't cause this creature to tap.)
Whenever a white creature you control attacks, you gain 1 life.

Idyllic Grange

({T}: Add {W}.)
Idyllic Grange enters tapped unless you control three or more other Plains.
When Idyllic Grange enters untapped, put a +1/+1 counter on target creature you control.

Gods Willing

Target creature you control gains protection from the color of your choice until end of turn. (It can't be blocked, targeted, dealt damage, enchanted, or equipped by anything of that color.)
Scry 1.

Loyal Pegasus

Flying
Loyal Pegasus can't attack or block alone.

Congregate

Target player gains 2 life for each creature on the battlefield.

Storm Herd

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