Siege Veteran

At the beginning of combat on your turn, put a +1/+1 counter on target creature you control.
Whenever another nontoken Soldier you control dies, create a 1/1 colorless Soldier artifact creature token.

Esper Sentinel

Whenever an opponent casts their first noncreature spell each turn, draw a card unless that player pays {X}, where X is this creature's power.

Yotian Frontliner

Whenever this creature attacks, another target creature you control gets +1/+1 until end of turn.
Unearth {W} ({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.)

Goldnight Commander

Whenever another creature you control enters, creatures you control get +1/+1 until end of turn.

Thalia, Guardian of Thraben

First strike
Noncreature spells cost {1} more to cast.

Thalia, Heretic Cathar

First strike
Creatures and nonbasic lands your opponents control enter tapped.

Valiant Veteran

Other Soldiers you control get +1/+1.
{3}{W}{W}, Exile this card from your graveyard: Put a +1/+1 counter on each Soldier you control.

Plains

Plains // Plains

Field Marshal

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

Rescue Retriever

Flash
When this creature enters, put a +1/+1 counter on each other Soldier you control.
Prevent all damage that would be dealt to other attacking Soldiers you control.

Coppercoat Vanguard

Each other Human you control gets +1/+0 and has ward {1}. (Whenever it becomes the target of a spell or ability an opponent controls, counter it unless that player pays {1}.)

Myrel, Shield of Argive

During your turn, your opponents can't cast spells or activate abilities of artifacts, creatures, or enchantments.
Whenever Myrel attacks, create X 1/1 colorless Soldier artifact creature tokens, where X is the number of Soldiers you control.