Skittering Precursor

Devoid (This card has no color.)
Menace
Whenever you sacrifice a nontoken permanent, create a 0/1 colorless Eldrazi Spawn creature token with "Sacrifice this token: Add {C}."

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.)

Crime Novelist

Whenever you sacrifice an artifact, put a +1/+1 counter on this creature and add {R}.

Exuberant Fuseling

Trample
This creature gets +1/+0 for each oil counter on it.
When this creature enters and whenever another creature or artifact you control is put into a graveyard from the battlefield, put an oil counter on this creature.

Magnetic Snuffler

When this creature enters, return target Equipment card from your graveyard to the battlefield attached to this creature.
Whenever you sacrifice an artifact, put a +1/+1 counter on this creature.

Havoc Jester

Whenever you sacrifice a permanent, this creature deals 1 damage to any target.

Blood Aspirant

Whenever you sacrifice a permanent, put a +1/+1 counter on this creature.
{1}{R}, {T}, Sacrifice a creature or enchantment: This creature deals 1 damage to target creature. That creature can't block this turn.

Dragonspark Reactor

Whenever this artifact or another artifact you control enters, put a charge counter on this artifact.
{4}, Sacrifice this artifact: It deals damage equal to the number of charge counters on it to target player and that much damage to up to one target creature.

Farid, Enterprising Salvager

Whenever a nontoken artifact you control is put into a graveyard from the battlefield, create a colorless artifact token named Scrap.
{1}{R}, Sacrifice an artifact: Choose one —
• Put a +1/+1 counter on Farid. It gains menace until end of turn.
• Goad target creature.
• Discard a card, then draw a card.

Krenko, Baron of Tin Street

Haste
{T}, Sacrifice an artifact: Put a +1/+1 counter on each Goblin you control.
Whenever an artifact is put into a graveyard from the battlefield, you may pay {R}. If you do, create a 1/1 red Goblin creature token. It gains haste until end of turn.

Tavern Scoundrel

Whenever you win a coin flip, create two Treasure tokens. (They're artifacts with "{T}, Sacrifice this token: Add one mana of any color.")
{1}, {T}, Sacrifice another permanent: Flip a coin.

Evendo Brushrazer

Whenever you sacrifice a nontoken permanent, exile the top card of your library.
During your turn, as long as you've sacrificed a nontoken permanent this turn, you may play cards exiled with this creature.
{T}, Sacrifice a land: Add {R}{R}.

Firion, Wild Rose Warrior

Equipped creatures you control have haste.
Whenever a nontoken Equipment you control enters, create a token that's a copy of it, except it has "This Equipment's equip abilities cost {2} less to activate." Sacrifice that token at the beginning of the next upkeep.