Serum Powder

{T}: Add {C}.
Any time you could mulligan and Serum Powder is in your hand, you may exile all the cards from your hand, then draw that many cards. (You can do this in addition to taking mulligans.)

Urza's Power Plant

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

Urza's Workshop

{T}: Add {C}.
Metalcraft — {T}: Add {C} for each Urza's land you control. Activate only if you control three or more artifacts.

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.

Mighty Servant of Leuk-o

Trample
Ward—Discard a card.
Whenever Mighty Servant of Leuk-o becomes crewed for the first time each turn, if it was crewed by exactly two creatures, it gains "Whenever this creature deals combat damage to a player, draw two cards" until end of turn.
Crew 4

Wastes

Urza's Mine

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

Expedition Map

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

Foundry Inspector

Artifact spells you cast cost {1} less to cast.

Steel Overseer

{T}: Put a +1/+1 counter on each artifact creature you control.

Lodestone Golem

Nonartifact spells cost {1} more to cast.

Mine Worker

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

Staff of Domination

{1}: Untap Staff of Domination.
{2}, {T}: You gain 1 life.
{3}, {T}: Untap target creature.
{4}, {T}: Tap target creature.
{5}, {T}: Draw a card.

Mazemind Tome

{T}, Put a page counter on this artifact: Scry 1. (Look at the top card of your library. You may put that card on the bottom.)
{2}, {T}, Put a page counter on this artifact: Draw a card.
When there are four or more page counters on this artifact, exile it. If you do, you gain 4 life.

Urza's Tower

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