Dispatch

Tap target creature.
Metalcraft — If you control three or more artifacts, exile that creature.

Divine Offering

Destroy target artifact. You gain life equal to its mana value.

Frogmite

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

Welding Jar

Sacrifice Welding Jar: Regenerate target artifact.

Ancient Den

Myr Enforcer

Seat of the Synod

Galvanic Blast

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

Darksteel Citadel

Sojourner's Companion

Affinity for artifacts
Artifact landcycling {2} ({2}, Discard this card: Search your library for an artifact land card, reveal it, put it into your hand, then shuffle.)

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.

Thought Monitor

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

Thoughtcast

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

Ornithopter

Great Furnace

Memnite

Molten Psyche

Each player shuffles the cards from their hand into their library, then draws that many cards.
Metalcraft — If you control three or more artifacts, Molten Psyche deals damage to each opponent equal to the number of cards that player has drawn this turn.