Mirran Crusader

Double strike, protection from black and from green

White Shield Crusader

Protection from black
{W}: White Shield Crusader gains flying until end of turn.
{W}{W}: White Shield Crusader gets +1/+0 until end of turn.

Hand of Honor

Protection from black
Bushido 1 (Whenever this creature blocks or becomes blocked, it gets +1/+1 until end of turn.)

White Sun's Zenith

Create X 2/2 white Cat creature tokens. Shuffle White Sun's Zenith into its owner's library.

Akroma, Angel of Wrath

Flying, first strike, vigilance, trample, haste, protection from black and from red

Whitesun's Passage

White Knight

First strike (This creature deals combat damage before creatures without first strike.)
Protection from black (This creature can't be blocked, targeted, dealt damage, or enchanted by anything black.)

Nahiri, the Lithomancer

+2: Create a 1/1 white Kor Soldier creature token. You may attach an Equipment you control to it.
−2: You may put an Equipment card from your hand or graveyard onto the battlefield.
−10: Create a colorless Equipment artifact token named Stoneforged Blade. It has indestructible, "Equipped creature gets +5/+5 and has double strike," and equip {0}.
Nahiri, the Lithomancer can be your commander.

White Sun's Twilight

You gain X life. Create X 1/1 colorless Phyrexian Mite artifact creature tokens with toxic 1 and "This creature can't block." If X is 5 or more, destroy all other creatures. (Players dealt combat damage by a creature with toxic 1 also get a poison counter.)

White Plume Adventurer

When White Plume Adventurer enters the battlefield, you take the initiative.
At the beginning of each opponent's upkeep, untap a creature you control. If you've completed a dungeon, untap all creatures you control instead.

White Dragon

Flying
Cold Breath — When White Dragon enters the battlefield, tap target creature an opponent controls. That creature doesn't untap during its controller's next untap step.

Protector of Gondor

When Protector of Gondor enters the battlefield, create a 1/1 white Human Soldier creature token.

Valor

First strike
As long as Valor is in your graveyard and you control a Plains, creatures you control have first strike.

White Mana Battery

{2}, {T}: Put a charge counter on White Mana Battery.
{T}, Remove any number of charge counters from White Mana Battery: Add {W}, then add an additional {W} for each charge counter removed this way.