Gut, True Soul Zealot

Whenever you attack, you may sacrifice another creature or an artifact. If you do, create a 4/1 black Skeleton creature token with menace that's tapped and attacking. (It can't be blocked except by two or more creatures.)
Choose a Background (You can have a Background as a second commander.)

Lozhan, Dragons' Legacy

Flying
Whenever you cast an Adventure or Dragon spell, Lozhan deals damage equal to that spell's mana value to any target that isn't a commander.

Sphinx of Magosi

Flying
{2}{U}: Draw a card, then put a +1/+1 counter on this creature.

Lavastep Raider

{2}{R}: This creature gets +2/+0 until end of turn.

Storm Fleet Sprinter

Gluntch, the Bestower

Flying
At the beginning of your end step, choose a player. They put two +1/+1 counters on a creature they control. Choose a second player to draw a card. Then choose a third player to create two Treasure tokens.

Fanatical Firebrand

Haste (This creature can attack and {T} as soon as it comes under your control.)
{T}, Sacrifice this creature: It deals 1 damage to any target.