Syndicate Trafficker

{1}, Sacrifice an artifact: Put a +1/+1 counter on Syndicate Trafficker. It gains indestructible until end of turn.

Time Sieve

{T}, Sacrifice five artifacts: Take an extra turn after this one.

Sly Requisitioner

Improvise (Your artifacts can help cast this spell. Each artifact you tap after you're done activating mana abilities pays for {1}.)
Whenever a nontoken artifact you control is put into a graveyard from the battlefield, create a 1/1 colorless Servo artifact creature token.

Mirrodin Besieged

As Mirrodin Besieged enters, choose Mirran or Phyrexian.
• Mirran — Whenever you cast an artifact spell, create a 1/1 colorless Myr artifact creature token.
• Phyrexian — At the beginning of your end step, draw a card, then discard a card. Then if there are fifteen or more artifact cards in your graveyard, target opponent loses the game.

Witching Well

When Witching Well enters, scry 2. (Look at the top two cards of your library, then put any number of them on the bottom and the rest on top in any order.)
{3}{U}, Sacrifice Witching Well: Draw two cards.

Revel in Riches

Whenever a creature an opponent controls dies, create a Treasure token. (It's an artifact with "{T}, Sacrifice this artifact: Add one mana of any color.")
At the beginning of your upkeep, if you control ten or more Treasures, you win the game.

Scrounge

Target opponent chooses an artifact card in their graveyard. Put that card onto the battlefield under your control.

Stoic Rebuttal

Metalcraft — This spell costs {1} less to cast if you control three or more artifacts.
Counter target spell.

Tezzeret the Schemer

+1: Create a colorless artifact token named Etherium Cell with "{T}, Sacrifice this artifact: Add one mana of any color."
−2: Target creature gets +X/-X until end of turn, where X is the number of artifacts you control.
−7: You get an emblem with "At the beginning of combat on your turn, target artifact you control becomes an artifact creature with base power and toughness 5/5."

Contraband Kingpin

Lifelink
Whenever an artifact you control enters, scry 1.

Marionette Master

Fabricate 3 (When this creature enters, put three +1/+1 counters on it or create three 1/1 colorless Servo artifact creature tokens.)
Whenever an artifact you control is put into a graveyard from the battlefield, target opponent loses life equal to Marionette Master's power.

Echo Storm

When you cast this spell, copy it for each time you've cast your commander from the command zone this game. You may choose new targets for the copies.
Create a token that's a copy of target artifact.

Efficient Construction

Whenever you cast an artifact spell, create a 1/1 colorless Thopter artifact creature token with flying.

Beacon of Unrest

Put target artifact or creature card from a graveyard onto the battlefield under your control. Shuffle Beacon of Unrest into its owner's library.

Gild

Exile target creature. Create a Gold token. (It's an artifact with "Sacrifice this artifact: Add one mana of any color.")

Mycosynth Wellspring

When Mycosynth Wellspring enters or is put into a graveyard from the battlefield, you may search your library for a basic land card, reveal it, put it into your hand, then shuffle.

Rona, Disciple of Gix

When Rona, Disciple of Gix enters, you may exile target historic card from your graveyard. (Artifacts, legendaries, and Sagas are historic.)
You may cast spells from among cards exiled with Rona.
{4}, {T}: Exile the top card of your library.

Tribute Mage

When Tribute Mage enters, you may search your library for an artifact card with mana value 2, reveal that card, put it into your hand, then shuffle.

Rebuild

Return all artifacts to their owners' hands.
Cycling {2} ({2}, Discard this card: Draw a card.)

Servo Schematic

When Servo Schematic enters or is put into a graveyard from the battlefield, create a 1/1 colorless Servo artifact creature token.

Etherium Astrolabe

Flash
{B}, {T}, Sacrifice an artifact: Draw a card.

Spell Swindle

Counter target spell. Create X Treasure tokens, where X is that spell's mana value. (They're artifacts with "{T}, Sacrifice this artifact: Add one mana of any color.")

Ichor Wellspring

When Ichor Wellspring enters or is put into a graveyard from the battlefield, draw a card.