Signal Pest

Battle cry (Whenever this creature attacks, each other attacking creature gets +1/+0 until end of turn.)
Signal Pest can't be blocked except by creatures with flying or reach.

Power Depot

Power Depot enters tapped.
{T}: Add {C}.
{T}: Add one mana of any color. Spend this mana only to cast artifact spells or activate abilities of artifacts.
Modular 1

Thoughtcast

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

Island

Broodstar

Affinity for artifacts (This spell costs {1} less to cast for each artifact you control.)
Flying
Broodstar's power and toughness are each equal to the number of artifacts you control.

Thought Monitor

Affinity for artifacts
Flying
When Thought Monitor enters, draw two cards.

Spell Pierce

Counter target noncreature spell unless its controller pays {2}.

Etched Champion

Metalcraft — Etched Champion has protection from each color as long as you control three or more artifacts.

Soul-Guide Lantern

When Soul-Guide Lantern enters, exile target card from a graveyard.
{T}, Sacrifice Soul-Guide Lantern: Exile each opponent's graveyard.
{1}, {T}, Sacrifice Soul-Guide Lantern: Draw a card.

Darksteel Citadel

Steel Sabotage

Choose one —
• Counter target artifact spell.
• Return target artifact to its owner's hand.

Myr Enforcer

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

Memnite

Ornithopter

Pithing Needle

As Pithing Needle enters, choose a card name.
Activated abilities of sources with the chosen name can't be activated unless they're mana abilities.

Fading Hope

Return target creature to its owner's hand. If its mana value was 3 or less, scry 1. (Look at the top card of your library. You may put that card on the bottom.)

Frogmite

Springleaf Drum

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

Mishra's Bauble

{T}, Sacrifice Mishra's Bauble: Look at the top card of target player's library. Draw a card at the beginning of the next turn's upkeep.

Assert Authority

Affinity for artifacts (This spell costs {1} less to cast for each artifact you control.)
Counter target spell. If that spell is countered this way, exile it instead of putting it into its owner's graveyard.