Horn of Gondor

When Horn of Gondor enters, create a 1/1 white Human Soldier creature token.
{3}, {T}: Create X 1/1 white Human Soldier creature tokens, where X is the number of Humans you control.

General Ferrous Rokiric

Hexproof from monocolored
Whenever you cast a multicolored spell, create a 4/4 red and white Golem artifact creature token.

Théoden, King of Rohan

Whenever Théoden, King of Rohan or another Human you control enters, target creature gains double strike until end of turn.

Swords to Plowshares

Exile target creature. Its controller gains life equal to its power.

Fervent Champion

First strike, haste
Whenever Fervent Champion attacks, another target attacking Knight you control gets +1/+0 until end of turn.
Equip abilities you activate that target Fervent Champion cost {3} less to activate.

Éomer, King of Rohan

Double strike
Éomer, King of Rohan enters with a +1/+1 counter on it for each other Human you control.
When Éomer enters, target player becomes the monarch. Éomer deals damage equal to its power to any target.

Plains

Ranger's Firebrand

Ranger's Firebrand deals 2 damage to any target. The Ring tempts you.

Rising of the Day

Creatures you control have haste.
Legendary creatures you control get +1/+0.

Champion of the Parish

Whenever another Human enters under your control, put a +1/+1 counter on Champion of the Parish.

Mirror Box

The "legend rule" doesn't apply to permanents you control.
Each legendary creature you control gets +1/+1.
Each nontoken creature you control gets +1/+1 for each other creature you control with the same name as that creature.

Éomer, Marshal of Rohan

Haste
Whenever one or more other attacking legendary creatures you control die, untap all creatures you control. After this phase, there is an additional combat phase. This ability triggers only once each turn.

Mountain

Riders of Rohan

When Riders of Rohan enters, create two 2/2 red Human Knight creature tokens with trample and haste.
Dash {4}{R}{W} (You may cast this spell for its dash cost. If you do, it gains haste, and it's returned from the battlefield to its owner's hand at the beginning of the next end step.)