Stormblood Berserker

Bloodthirst 2 (If an opponent was dealt damage this turn, this creature enters with two +1/+1 counters on it.)
Menace (This creature can't be blocked except by two or more creatures.)

Urabrask the Hidden

Creatures you control have haste.
Creatures your opponents control enter tapped.

Lightning Berserker

{R}: This creature gets +1/+0 until end of turn.
Dash {R} (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.)

Hardened Berserker

Whenever this creature attacks, the next spell you cast this turn costs {1} less to cast.

Karlach, Fury of Avernus

Whenever you attack, if it's the first combat phase of the turn, untap all attacking creatures. They gain first strike until end of turn. After this phase, there is an additional combat phase.
Choose a Background (You can have a Background as a second commander.)

Keldon Berserker

Whenever this creature attacks, if you control no untapped lands, it gets +3/+0 until end of turn.

Unchained Berserker

Protection from white (This creature can't be blocked, targeted, dealt damage, enchanted, or equipped by anything white.)
This creature gets +2/+0 as long as it's attacking.

Sardian Cliffstomper

As long as it's your turn and you control four or more Mountains, this creature gets +X/+0, where X is the number of Mountains you control.

Kuldotha Ringleader

Battle cry (Whenever this creature attacks, each other attacking creature gets +1/+0 until end of turn.)
This creature attacks each combat if able.

Cinderheart Giant

Trample
When this creature dies, it deals 7 damage to a creature an opponent controls chosen at random.

Balthor the Stout

Other Barbarian creatures get +1/+1.
{R}: Another target Barbarian creature gets +1/+0 until end of turn.

Lightning Mauler

Soulbond (You may pair this creature with another unpaired creature when either enters. They remain paired for as long as you control both of them.)
As long as this creature is paired with another creature, both creatures have haste.

Keldon Warlord

Keldon Warlord's power and toughness are each equal to the number of non-Wall creatures you control.

Aerathi Berserker

Rampage 3 (Whenever this creature becomes blocked, it gets +3/+3 until end of turn for each creature blocking it beyond the first.)

Barbarian General

Horsemanship (This creature can't be blocked except by creatures with horsemanship.)

Lovisa Coldeyes

Each creature that's a Barbarian, a Warrior, or a Berserker gets +2/+2 and has haste.