Metallic Rebuke

Improvise (Your artifacts can help cast this spell. Each artifact you tap after you're done activating mana abilities pays for {1}.)
Counter target spell unless its controller pays {3}.

Silverbluff Bridge

This land enters tapped.
Indestructible
{T}: Add {U} or {R}.

Gearseeker Serpent

Affinity for artifacts (This spell costs {1} less to cast for each artifact you control.)
{5}{U}: This creature can't be blocked this turn.

Cryogen Relic

When this artifact enters or leaves the battlefield, draw a card.
{1}{U}, Sacrifice this artifact: Put a stun counter on up to one target tapped creature. (If a permanent with a stun counter would become untapped, remove one from it instead.)

Seat of the Synod

Great Furnace

Electrickery

Electrickery deals 1 damage to target creature you don't control.
Overload {1}{R} (You may cast this spell for its overload cost. If you do, change "target" in its text to "each.")

Hydroblast

Choose one —
• Counter target spell if it's red.
• Destroy target permanent if it's red.

Kenku Artificer

Homunculus Servant — When this creature enters, put three +1/+1 counters on up to one target noncreature artifact. That artifact becomes a 0/0 Homunculus artifact creature with flying.

Darksteel Citadel

Gorilla Shaman

{X}{X}{1}: Destroy target noncreature artifact with mana value X.

Frogmite

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

Flayer Husk

Living weapon (When this Equipment enters, create a 0/0 black Phyrexian Germ creature token, then attach this to it.)
Equipped creature gets +1/+1.
Equip {2}

Relic of Progenitus

{T}: Target player exiles a card from their graveyard.
{1}, Exile this artifact: Exile all graveyards. Draw a card.

Ornithopter

Galvanic Blast

Galvanic Blast deals 2 damage to any target.
Metalcraft — Galvanic Blast deals 4 damage instead if you control three or more artifacts.

Island

Turn Aside

Counter target spell that targets a permanent you control.

Moon-Circuit Hacker

Ninjutsu {U} ({U}, Return an unblocked attacker you control to hand: Put this card onto the battlefield from your hand tapped and attacking.)
Whenever this creature deals combat damage to a player, you may draw a card. If you do, discard a card unless this creature entered this turn.

Dispel

Myr Enforcer

Pyroblast

Choose one —
• Counter target spell if it's blue.
• Destroy target permanent if it's blue.

Springleaf Drum

{T}, Tap an untapped creature you control: Add one mana of any color.

Thoughtcast

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