Valor

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

Knight of the White Orchid

First strike
When Knight of the White Orchid enters, if an opponent controls more lands than you, you may search your library for a Plains card, put it onto the battlefield, then shuffle.

Keeper of the Accord

At the beginning of each opponent's end step, if that player controls more creatures than you, create a 1/1 white Soldier creature token.
At the beginning of each opponent's end step, if that player controls more lands than you, you may search your library for a basic Plains card, put it onto the battlefield tapped, then shuffle.

Intangible Virtue

Creature tokens you control get +1/+1 and have vigilance.

Kwende, Pride of Femeref

Double strike
Creatures you control with first strike have double strike.

Precinct Captain

First strike
Whenever Precinct Captain deals combat damage to a player, create a 1/1 white Soldier creature token.

Heraldic Banner

As this artifact enters, choose a color.
Creatures you control of the chosen color get +1/+0.
{T}: Add one mana of the chosen color.

Archetype of Courage

Creatures you control have first strike.
Creatures your opponents control lose first strike and can't have or gain first strike.

Oketra's Monument

White creature spells you cast cost {1} less to cast.
Whenever you cast a creature spell, create a 1/1 white Warrior creature token with vigilance.