Retrieval Agent

{2}: Retrieval Agent gets +1/-1 until end of turn.

Air Marshal

{3}: Target Soldier gains flying until end of turn.

Disenchant

Ambush Paratrooper

Flash
Flying
{5}: Creatures you control get +1/+1 until end of turn.

Mass Production

Create four 1/1 colorless Soldier artifact creature tokens.

Swiftfoot Boots

Equipped creature has hexproof and haste. (It can't be the target of spells or abilities your opponents control. It can attack and {T} no matter when it came under your control.)
Equip {1} ({1}: Attach to target creature you control. Equip only as a sorcery.)

Plains

Prison Sentence

Enchant creature
When Prison Sentence enters, scry 2.
Enchanted creature can't attack or block, and its activated abilities can't be activated.

The Mightstone and Weakstone

When The Mightstone and Weakstone enters, choose one —
• Draw two cards.
• Target creature gets -5/-5 until end of turn.
{T}: Add {C}{C}. This mana can't be spent to cast nonartifact spells.
(Melds with Urza, Lord Protector.)

Harbin, Vanguard Aviator

Flying
Whenever you attack with five or more Soldiers, creatures you control get +1/+1 and gain flying until end of turn.

Island

Static Net

When Static Net enters, exile target nonland permanent an opponent controls until Static Net leaves the battlefield.
When Static Net enters, you gain 2 life and create a tapped Powerstone token. (It's an artifact with "{T}: Add {C}. This mana can't be spent to cast a nonartifact spell.")

Recommission

Return target artifact or creature card with mana value 3 or less from your graveyard to the battlefield. If a creature enters this way, it enters with an additional +1/+1 counter on it.

Steel Seraph

Prototype {1}{W}{W} — 3/3 (You may cast this spell with different mana cost, color, and size. It keeps its abilities and types.)
Flying
At the beginning of combat on your turn, target creature you control gains your choice of flying, vigilance, or lifelink until end of turn.

Veteran's Powerblade

Equipped creature gets +2/+0.
Equip Soldier {W}
Equip {2} ({2}: Attach to target creature you control. Equip only as a sorcery.)

Wing Commando

Flying
Prowess (Whenever you cast a noncreature spell, this creature gets +1/+1 until end of turn.)

Weakstone's Subjugation

Enchant artifact or creature
When Weakstone's Subjugation enters, you may pay {3}. If you do, tap enchanted permanent.
Enchanted permanent doesn't untap during its controller's untap step.

Scrapwork Cohort

When Scrapwork Cohort enters, create a 1/1 colorless Soldier artifact creature token.
Unearth {2}{W} ({2}{W}: Return this card from your graveyard to the battlefield. It gains haste. Exile it at the beginning of the next end step or if it would leave the battlefield. Unearth only as a sorcery.)

Meticulous Excavation

{2}{W}: Return target permanent you control to its owner's hand. If it has unearth, instead exile it, then return that card to its owner's hand. Activate only during your turn.

Warlord's Elite

As an additional cost to cast this spell, tap two untapped artifacts, creatures, and/or lands you control.

Great Desert Prospector

When Great Desert Prospector enters, create a tapped Powerstone token for each other creature you control. (They're artifacts with "{T}: Add {C}. This mana can't be spent to cast a nonartifact spell.")

Loran, Disciple of History

Whenever Loran, Disciple of History or another legendary creature you control enters, return target artifact card from your graveyard to your hand.

Spotter Thopter

Prototype {3}{U} — 2/3 (You may cast this spell with different mana cost, color, and size. It keeps its abilities and types.)
Flying
When Spotter Thopter enters, scry X, where X is its power.

Aeronaut Cavalry

Flying
When Aeronaut Cavalry enters, put a +1/+1 counter on another target Soldier you control.