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.

Liquimetal Coating

{T}: Target permanent becomes an artifact in addition to its other types 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.

Prototype Portal

Imprint — When Prototype Portal enters the battlefield, you may exile an artifact card from your hand.
{X}, {T}: Create a token that's a copy of the exiled card. X is the mana value of that card.

Urza's Tower

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

Self-Assembler

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

Steel Hellkite

Flying
{2}: Steel Hellkite gets +1/+0 until end of turn.
{X}: Destroy each nonland permanent with mana value X whose controller was dealt combat damage by Steel Hellkite this turn. Activate only once each turn.

Spy Kit

Equipped creature gets +1/+1 and has all names of nonlegendary creature cards in addition to its name.
Equip {2}

Mine Worker

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

Cogwork Assembler

{7}: Create a token that's a copy of target artifact. That token gains haste. Exile it at the beginning of the next end step.

Jetfire, Air Guardian

Living metal (As long as it's your turn, this Vehicle is also a creature.)
Flying
{U}{U}{U}: Convert Jetfire, then adapt 3. (If it has no +1/+1 counters on it, put three +1/+1 counters on it.)

Jetfire, Ingenious Scientist

More Than Meets the Eye {3}{U} (You may cast this card converted for {3}{U}.)
Flying
Remove one or more +1/+1 counters from among artifacts you control: Target player adds that much {C}. This mana can't be spent to cast nonartifact spells. Convert Jetfire.

Jetfire, Ingenious Scientist // Jetfire, Air Guardian

Urza's Power Plant

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

Mechtitan Core

{5}, Exile Mechtitan Core and four other artifact creatures and/or Vehicles you control: Create Mechtitan, a legendary 10/10 Construct artifact creature token with flying, vigilance, trample, lifelink, and haste that's all colors. When that token leaves the battlefield, return all cards exiled with Mechtitan Core except Mechtitan Core to the battlefield tapped under their owners' control.
Crew 2

Mindlink Mech

Flying
Whenever Mindlink Mech becomes crewed for the first time each turn, until end of turn, Mindlink Mech becomes a copy of target nonlegendary creature that crewed it this turn, except it's 4/3, it's a Vehicle artifact in addition to its other types, and it has flying.
Crew 1

Synod Artificer

{X}, {T}: Tap X target noncreature artifacts.
{X}, {T}: Untap X target noncreature artifacts.

March of the Machines

Each noncreature artifact is an artifact creature with power and toughness each equal to its mana value. (Equipment that's a creature can't equip a creature.)

Inexorable Tide

Whenever you cast a spell, proliferate. (Choose any number of permanents and/or players, then give each another counter of each kind already there.)

Urza's Mine

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

Urza's Factory

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