Darksteel Citadel

Breath Weapon

Breath Weapon deals 2 damage to each non-Dragon creature.

Plundering Barbarian

When Plundering Barbarian enters, choose one —
• Smash the Chest — Destroy target artifact.
• Pry It Open — Create a Treasure token. (It's an artifact with "{T}, Sacrifice this artifact: Add one mana of any color.")

End the Festivities

End the Festivities deals 1 damage to each opponent and each creature and planeswalker they control.

Reckless Fireweaver

Whenever an artifact you control enters, Reckless Fireweaver deals 1 damage to each opponent.

Abrade

Choose one —
• Abrade deals 3 damage to target creature.
• Destroy target artifact.

Great Furnace

Silverbluff Bridge

Silverbluff Bridge enters tapped.
Indestructible
{T}: Add {U} or {R}.

Of One Mind

This spell costs {2} less to cast if you control a Human creature and a non-Human creature.
Draw two cards.

Reckless Impulse

Exile the top two cards of your library. Until the end of your next turn, you may play those cards.

Myr Enforcer

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

Experimental Synthesizer

When Experimental Synthesizer enters or leaves the battlefield, exile the top card of your library. Until end of turn, you may play that card.
{2}{R}, Sacrifice Experimental Synthesizer: Create a 2/2 white Samurai creature token with vigilance. Activate only as a sorcery.

Shrapnel Slinger

When Shrapnel Slinger enters, you may sacrifice a creature. When you do, destroy target artifact an opponent controls.

Yavimaya Steelcrusher

Enlist (As this creature attacks, you may tap a nonattacking creature you control without summoning sickness. When you do, add its power to this creature's until end of turn.)
{1}, Sacrifice Yavimaya Steelcrusher: Destroy target artifact.

Springleaf Drum

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

Cast into the Fire

Choose one —
• Cast into the Fire deals 1 damage to each of up to two target creatures.
• Exile target artifact.

Blue Elemental Blast

Choose one —
• Counter target red spell.
• Destroy target red permanent.

Towashi Songshaper

Whenever another artifact you control enters, Towashi Songshaper gets +1/+0 until end of turn.

Galvanic Blast

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

Krark-Clan Shaman

Sacrifice an artifact: Krark-Clan Shaman deals 1 damage to each creature without flying.

Salivating Gremlins

Whenever an artifact you control enters, Salivating Gremlins gets +2/+0 and gains trample until end of turn.

Gorilla Shaman

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

Relic of Progenitus

{T}: Target player exiles a card from their graveyard.
{1}, Exile Relic of Progenitus: Exile all graveyards. Draw a card.

Island

Thoughtcast

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

Seat of the Synod

Smash to Dust

Choose one —
• Destroy target artifact.
• Destroy target creature with defender.
• Smash to Dust deals 1 damage to each creature your opponents control.

Fiery Cannonade

Fiery Cannonade deals 2 damage to each non-Pirate creature.

Frogmite

Smash to Smithereens

Destroy target artifact. Smash to Smithereens deals 3 damage to that artifact's controller.

Etherium Spinner

Whenever you cast a spell with mana value 4 or greater, create a 1/1 colorless Thopter artifact creature token with flying.

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}.

Lightning Bolt

Lightning Bolt deals 3 damage to any target.

Voldaren Epicure

When Voldaren Epicure enters, it deals 1 damage to each opponent. Create a Blood token. (It's an artifact with "{1}, {T}, Discard a card, Sacrifice this artifact: Draw a card.")

Mountain

Kenku Artificer

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

Ornithopter

Ingenious Artillerist

Whenever one or more artifacts you control enter, Ingenious Artillerist deals that much damage to each opponent.