Gideon's Avenger

Whenever a creature an opponent controls becomes tapped, put a +1/+1 counter on Gideon's Avenger.

Plains

Spear of Heliod

Creatures you control get +1/+1.
{1}{W}{W}, {T}: Destroy target creature that dealt damage to you this turn.

Paragon of New Dawns

Other white creatures you control get +1/+1.
{W}, {T}: Another target white creature you control gains vigilance until end of turn. (Attacking doesn't cause it to tap.)

Concerted Effort

At the beginning of each upkeep, creatures you control gain flying until end of turn if a creature you control has flying. The same is true for fear, first strike, double strike, landwalk, protection, trample, and vigilance.

Emeria, the Sky Ruin

Emeria, the Sky Ruin enters tapped.
At the beginning of your upkeep, if you control seven or more Plains, you may return target creature card from your graveyard to the battlefield.
{T}: Add {W}.

Rootborn Defenses

Populate. Creatures you control gain indestructible until end of turn. (To populate, create a token that's a copy of a creature token you control.)

Oblivion Ring

When Oblivion Ring enters, exile another target nonland permanent.
When Oblivion Ring leaves the battlefield, return the exiled card to the battlefield under its owner's control.

Rhox Pikemaster

First strike (This creature deals combat damage before creatures without first strike.)
Other Soldier creatures you control have first strike.

Endless Horizons

When Endless Horizons enters, search your library for any number of Plains cards, exile them, then shuffle.
At the beginning of your upkeep, you may put a card you own exiled with Endless Horizons into your hand.

Armored Ascension

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

Entrapment Maneuver

Target player sacrifices an attacking creature of their choice. You create X 1/1 white Soldier creature tokens, where X is that creature's toughness.

New Benalia

New Benalia enters tapped.
When New Benalia enters, scry 1. (Look at the top card of your library. You may put that card on the bottom.)
{T}: Add {W}.

Field Marshal

Other Soldier creatures get +1/+1 and have first strike. (They deal combat damage before creatures without first strike.)

Return to Dust

Exile target artifact or enchantment. If you cast this spell during your main phase, you may exile up to one other target artifact or enchantment.

Akrasan Squire

Exalted (Whenever a creature you control attacks alone, that creature gets +1/+1 until end of turn.)

Smothering Tithe

Whenever an opponent draws a card, that player may pay {2}. If the player doesn't, you create a Treasure token. (It's an artifact with "{T}, Sacrifice this artifact: Add one mana of any color.")

Captain of the Watch

Vigilance (Attacking doesn't cause this creature to tap.)
Other Soldier creatures you control get +1/+1 and have vigilance.
When Captain of the Watch enters, create three 1/1 white Soldier creature tokens.

Intrepid Hero

{T}: Destroy target creature with power 4 or greater.

Herald's Horn

As Herald's Horn enters, choose a creature type.
Creature spells you cast of the chosen type cost {1} less to cast.
At the beginning of your upkeep, look at the top card of your library. If it's a creature card of the chosen type, you may reveal it and put it into your hand.

Guildscorn Ward

Enchant creature
Enchanted creature has protection from multicolored.

Aven Squire

Flying
Exalted (Whenever a creature you control attacks alone, that creature gets +1/+1 until end of turn.)

Glorious Anthem

Veteran Armorsmith

Other Soldier creatures you control get +0/+1.

Gideon's Lawkeeper

Honor of the Pure

Marshal's Anthem

Multikicker {1}{W} (You may pay an additional {1}{W} any number of times as you cast this spell.)
Creatures you control get +1/+1.
When Marshal's Anthem enters, return up to X target creature cards from your graveyard to the battlefield, where X is the number of times Marshal's Anthem was kicked.

Ballyrush Banneret

Kithkin spells and Soldier spells you cast cost {1} less to cast.

Palace Guard

Palace Guard can block any number of creatures.

Elspeth, Knight-Errant

+1: Create a 1/1 white Soldier creature token.
+1: Target creature gets +3/+3 and gains flying until end of turn.
−8: You get an emblem with "Artifacts, creatures, enchantments, and lands you control have indestructible."

Daru Warchief

Soldier spells you cast cost {1} less to cast.
Soldier creatures you control get +1/+2.

Goldmeadow Harrier

Deploy to the Front

Create X 1/1 white Soldier creature tokens, where X is the number of creatures on the battlefield.

Fencing Ace

Double strike (This creature deals both first-strike and regular combat damage.)

Holy Mantle

Enchant creature
Enchanted creature gets +2/+2 and has protection from creatures.

Cathars' Crusade

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

Spirit Mantle

Enchant creature
Enchanted creature gets +1/+1 and has protection from creatures.

Veteran Swordsmith

Other Soldier creatures you control get +1/+0.

Dictate of Heliod

Unbreakable Formation

Creatures you control gain indestructible until end of turn.
Addendum — If you cast this spell during your main phase, put a +1/+1 counter on each of those creatures and they gain vigilance until end of turn.