Otawara, Soaring City

{T}: Add {U}.
Channel — {3}{U}, Discard Otawara, Soaring City: Return target artifact, creature, enchantment, or planeswalker to its owner's hand. This ability costs {1} less to activate for each legendary creature you control.

Mountain

Tarrian's Soulcleaver

Equipped creature has vigilance.
Whenever another artifact or creature is put into a graveyard from the battlefield, put a +1/+1 counter on equipped creature.
Equip {2}

Third Path Iconoclast

Whenever you cast a noncreature spell, create a 1/1 colorless Soldier artifact creature token.

Iceberg Titan

Whenever Iceberg Titan attacks, you may tap or untap target artifact or creature.

Inverted Iceberg

When Inverted Iceberg enters, mill a card, then draw a card. (To mill a card, put the top card of your library into your graveyard.)
Craft with artifact {4}{U}{U} ({4}{U}{U}, Exile this artifact, Exile another artifact you control or an artifact card from your graveyard: Return this card transformed under its owner's control. Craft only as a sorcery.)

Inverted Iceberg // Iceberg Titan

Patchwork Automaton

Ward {2} (Whenever this creature becomes the target of a spell or ability an opponent controls, counter it unless that player pays {2}.)
Whenever you cast an artifact spell, put a +1/+1 counter on Patchwork Automaton.

Island

The Mycosynth Gardens

{T}: Add {C}.
{1}, {T}: Add one mana of any color.
{X}, {T}: The Mycosynth Gardens becomes a copy of target nontoken artifact you control with mana value X.

Syr Ginger, the Meal Ender

Syr Ginger, the Meal Ender has trample, hexproof, and haste as long as an opponent controls a planeswalker.
Whenever another artifact you control is put into a graveyard from the battlefield, put a +1/+1 counter on Syr Ginger and scry 1.
{2}, {T}, Sacrifice Syr Ginger: You gain life equal to its power.

Mirrex

{T}: Add {C}.
{T}: Add one mana of any color. Activate only if Mirrex entered this turn.
{3}, {T}: Create a 1/1 colorless Phyrexian Mite artifact creature token with toxic 1 and "This creature can't block." (Players dealt combat damage by it also get a poison counter.)

Sokenzan Smelter

At the beginning of combat on your turn, you may pay {1} and sacrifice an artifact. If you do, create a 3/1 red Construct artifact creature token with haste.

Geode Grotto

(Transforms from Dowsing Device.)
{T}: Add {R}.
{2}{R}, {T}: Until end of turn, target creature gains haste and gets +X/+0, where X is the number of artifacts you control. Activate only as a sorcery.

Dowsing Device

Whenever Dowsing Device or another artifact you control enters, up to one target creature you control gets +1/+0 and gains haste until end of turn. Then transform Dowsing Device if you control four or more artifacts.

Dowsing Device // Geode Grotto

Enthusiastic Mechanaut

Flying
Artifact spells you cast cost {1} less to cast.

Dire Blunderbuss

Equipped creature gets +3/+0 and has "Whenever this creature attacks, you may sacrifice an artifact other than Dire Blunderbuss. When you do, this creature deals damage equal to its power to target creature."
Equip {1}

Dire Flail

Equipped creature gets +2/+0.
Equip {1}
Craft with artifact {3}{R}{R} ({3}{R}{R}, Exile this artifact, Exile another artifact you control or an artifact card from your graveyard: Return this card transformed under its owner's control. Craft only as a sorcery.)

Dire Flail // Dire Blunderbuss

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.

Voltage Surge

As an additional cost to cast this spell, you may sacrifice an artifact.
Voltage Surge deals 2 damage to target creature or planeswalker. If this spell's additional cost was paid, Voltage Surge deals 4 damage instead.