Tower Worker

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

Assembly-Worker

{T}: Target Assembly-Worker creature gets +1/+1 until end of turn.

Urza's Power Plant

{T}: Add {C}. If you control an Urza's Mine and an Urza's Tower, add {C}{C} instead.

Power Plant Worker

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

Mine Worker

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

Expedition Map

{2}, {T}, Sacrifice this artifact: Search your library for a land card, reveal it, put it into your hand, then shuffle.

Self-Assembler

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

Urza's Mine

{T}: Add {C}. If you control an Urza's Power-Plant and an Urza's Tower, add {C}{C} instead.

Foundry Assembler

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

Urza's Tower

{T}: Add {C}. If you control an Urza's Mine and an Urza's Power-Plant, add {C}{C}{C} instead.

Dutiful Replicator

When this creature enters, you may pay {1}. When you do, create a token that's a copy of target token you control not named Dutiful Replicator.