Veteran Armorsmith

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

Plains

Kitesail Apprentice

As long as Kitesail Apprentice is equipped, it gets +1/+1 and has flying.

Evolving Wilds

{T}, Sacrifice this land: Search your library for a basic land card, put it onto the battlefield tapped, then shuffle.

Unified Strike

Exile target attacking creature if its power is less than or equal to the number of Soldiers on the battlefield.

Leonin Den-Guard

As long as Leonin Den-Guard is equipped, it gets +1/+1 and has vigilance.

Bonesplitter

Sunspear Shikari

As long as Sunspear Shikari is equipped, it has first strike and lifelink. (It deals combat damage before creatures without first strike. Damage dealt by it also causes you to gain that much life.)

Bone Saw

Equipped creature gets +1/+0.
Equip {1} ({1}: Attach to target creature you control. Equip only as a sorcery.)

Auriok Glaivemaster

As long as Auriok Glaivemaster is equipped, it gets +1/+1 and has first strike.

Veteran Swordsmith

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

Adventuring Gear

Landfall — Whenever a land you control enters, equipped creature gets +2/+2 until end of turn.
Equip {1} ({1}: Attach to target creature you control. Equip only as a sorcery.)