Urza's Mine

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

Pierce Strider

When Pierce Strider enters the battlefield, target opponent loses 3 life.

Rust Goliath

Prototype {3}{G}{G} — 3/5 (You may cast this spell with different mana cost, color, and size. It keeps its abilities and types.)
Reach, trample

Myr Servitor

At the beginning of your upkeep, if Myr Servitor is on the battlefield, each player returns all cards named Myr Servitor from their graveyard to the battlefield.

Darksteel Citadel

Corpse Cur

Infect (This creature deals damage to creatures in the form of -1/-1 counters and to players in the form of poison counters.)
When Corpse Cur enters the battlefield, you may return target creature card with infect from your graveyard to your hand.

Tower Worker

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

Urza's Tower

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

Pardic Wanderer

Roving Keep

Defender
{7}: Roving Keep gets +2/+0 and gains trample until end of turn. It can attack this turn as though it didn't have defender.

Mine Worker

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

Mishra's Juggernaut

Trample
Mishra's Juggernaut attacks each combat if able.
Unearth {5}{R} ({5}{R}: Return this card from your graveyard to the battlefield. It gains haste. Exile it at the beginning of the next end step or if it would leave the battlefield. Unearth only as a sorcery.)

Frogmite

Affinity for artifacts (This spell costs {1} less to cast for each artifact you control.)

Maelstrom Colossus

Cascade (When you cast this spell, exile cards from the top of your library until you exile a nonland card that costs less. You may cast it without paying its mana cost. Put the exiled cards on the bottom of your library in a random order.)

Myr Enforcer

Assembly-Worker

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

Workshop Assistant

When Workshop Assistant dies, return another target artifact card from your graveyard to your hand.

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.

Expedition Map

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

Urza's Power Plant

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

Ichorclaw Myr

Infect (This creature deals damage to creatures in the form of -1/-1 counters and to players in the form of poison counters.)
Whenever Ichorclaw Myr becomes blocked, it gets +2/+2 until end of turn.

Glimmerpost

When Glimmerpost enters the battlefield, you gain 1 life for each Locus on the battlefield.
{T}: Add {C}.

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.