Herald of Kozilek

Devoid (This card has no color.)
Colorless spells you cast cost {1} less to cast.

Dominator Drone

Devoid (This card has no color.)
Ingest (Whenever this creature deals combat damage to a player, that player exiles the top card of their library.)
When Dominator Drone enters, if you control another colorless creature, each opponent loses 2 life.

Dust Stalker

Devoid (This card has no color.)
Haste
At the beginning of each end step, if you control no other colorless creatures, return Dust Stalker to its owner's hand.

Flayer Drone

Devoid (This card has no color.)
First strike
Whenever another colorless creature you control enters, target opponent loses 1 life.

Mishra's Self-Replicator

Whenever you cast a historic spell, you may pay {1}. If you do, create a token that's a copy of Mishra's Self-Replicator. (Artifacts, legendaries, and Sagas are historic.)

Mishra's Factory

{T}: Add {C}.
{1}: Mishra's Factory becomes a 2/2 Assembly-Worker artifact creature until end of turn. It's still a land.
{T}: Target Assembly-Worker creature gets +1/+1 until end of turn.

Foundry Assembler

Improvise (Your artifacts can help cast this spell. Each artifact you tap after you're done activating mana abilities pays for {1}.)

Power Plant Worker

{3}: Power Plant Worker gets +2/+2 until end of turn. If you control creatures named Mine Worker and Tower Worker, put two +1/+1 counters on Power Plant Worker instead. Activate only once each turn.

Self-Assembler

When Self-Assembler enters, you may search your library for an Assembly-Worker creature card, reveal it, put it into your hand, then shuffle.

Ghostfire Blade

Equipped creature gets +2/+2.
Equip {3}
Ghostfire Blade's equip ability costs {2} less to activate if it targets a colorless creature.

Nettle Drone

Devoid (This card has no color.)
{T}: Nettle Drone deals 1 damage to each opponent.
Whenever you cast a colorless spell, untap Nettle Drone.

Forsaken Monument

Colorless creatures you control get +2/+2.
Whenever you tap a permanent for {C}, add an additional {C}.
Whenever you cast a colorless spell, you gain 2 life.

Daretti, Ingenious Iconoclast

+1: Create a 1/1 colorless Construct artifact creature token with defender.
−1: You may sacrifice an artifact. If you do, destroy target artifact or creature.
−6: Choose target artifact card in a graveyard or artifact on the battlefield. Create three tokens that are copies of it.

Karn, Scion of Urza

+1: Reveal the top two cards of your library. An opponent chooses one of them. Put that card into your hand and exile the other with a silver counter on it.
−1: Put a card you own with a silver counter on it from exile into your hand.
−2: Create a 0/0 colorless Construct artifact creature token with "This creature gets +1/+1 for each artifact you control."

Cultivator Drone

Devoid (This card has no color.)
{T}: Add {C}. Spend this mana only to cast a colorless spell, activate an ability of a colorless permanent, or pay a cost that contains {C}. ({C} represents colorless mana.)

Autonomous Assembler

Prototype {1}{W} — 2/2 (You may cast this spell with different mana cost, color, and size. It keeps its abilities and types.)
Vigilance
{1}, {T}: Put a +1/+1 counter on target Assembly-Worker you control.

Arcbound Prototype

Modular 2 (This creature enters with two +1/+1 counters on it. When it dies, you may put its +1/+1 counters on target artifact creature.)

Molten Nursery

Devoid (This card has no color.)
Whenever you cast a colorless spell, Molten Nursery deals 1 damage to any target.

Urza's Factory

{T}: Add {C}.
{7}, {T}: Create a 2/2 colorless Assembly-Worker artifact creature token.

Mine Worker

{T}: You gain 1 life. If you control creatures named Power Plant Worker and Tower Worker, you gain 3 life instead.

Forerunner of Slaughter

Devoid (This card has no color.)
{1}: Target colorless creature gains haste until end of turn.

Tower Worker

Reach
{T}: Add {C}. If you control creatures named Mine Worker and Power Plant Worker, add {C}{C}{C} instead.