Adriana, Captain of the Guard

Melee (Whenever this creature attacks, it gets +1/+1 until end of turn for each opponent you attacked this combat.)
Other creatures you control have melee. (If a creature has multiple instances of melee, each triggers separately.)

Skyknight Vanguard

Flying
Whenever Skyknight Vanguard attacks, create a 1/1 white Soldier creature token that's tapped and attacking.

Malik, Grim Manipulator

When Malik, Grim Manipulator enters the battlefield, you and target opponent each secretly choose a creature that player controls. Then those choices are revealed, and that player sacrifices those creatures.
Whenever an opponent sacrifices a creature, you create a Treasure token.

Commissar Severina Raine

Leading from the Front — Whenever Commissar Severina Raine attacks, each opponent loses X life, where X is the number of other attacking creatures.
Summary Execution — {2}, Sacrifice another creature: You gain 2 life and draw a card.

Chainer, Nightmare Adept

Discard a card: You may cast a creature spell from your graveyard this turn. Activate only once each turn.
Whenever a nontoken creature enters the battlefield under your control, if you didn't cast it from your hand, it gains haste until your next turn.

Exava, Rakdos Blood Witch

First strike, haste
Unleash (You may have this creature enter the battlefield with a +1/+1 counter on it. It can't block as long as it has a +1/+1 counter on it.)
Each other creature you control with a +1/+1 counter on it has haste.

General Kudro of Drannith

Other Humans you control get +1/+1.
Whenever General Kudro of Drannith or another Human enters the battlefield under your control, exile target card from an opponent's graveyard.
{2}, Sacrifice two Humans: Destroy target creature with power 4 or greater.

Riders of Rohan

When Riders of Rohan enters the battlefield, 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.)

Tymna the Weaver

Lifelink
At the beginning of your postcombat main phase, you may pay X life, where X is the number of opponents that were dealt combat damage this turn. If you do, draw X cards.
Partner (You can have two commanders if both have partner.)

Forth Eorlingas!

Create X 2/2 red Human Knight creature tokens with trample and haste.
Whenever one or more creatures you control deal combat damage to one or more players this turn, you become the monarch.

Blade Historian

Attacking creatures you control have double strike.

Théoden, King of Rohan

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

Judith, the Scourge Diva

Other creatures you control get +1/+0.
Whenever a nontoken creature you control dies, Judith, the Scourge Diva deals 1 damage to any target.

Jirina Kudro

When Jirina Kudro enters the battlefield, create a 1/1 white Human Soldier creature token for each time you've cast a commander from the command zone this game.
Other Humans you control get +2/+0.

General's Enforcer

Legendary Humans you control have indestructible.
{2}{W}{B}: Exile target card from a graveyard. If it was a creature card, create a 1/1 white Human Soldier creature token.

Éowyn, Fearless Knight

Haste
When Éowyn, Fearless Knight enters the battlefield, exile target creature an opponent controls with greater power. Legendary creatures you control gain protection from each of that creature's colors until end of turn.

Jirina, Dauntless General

When Jirina, Dauntless General enters the battlefield, exile target player's graveyard.
Sacrifice Jirina: Humans you control gain hexproof and indestructible until end of turn.

Stormfist Crusader

Menace
At the beginning of your upkeep, each player draws a card and loses 1 life.

Éomer, King of Rohan

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