Master of Etherium

Master of Etherium's power and toughness are each equal to the number of artifacts you control.
Other artifact creatures you control get +1/+1.

Rebbec, Architect of Ascension

Artifacts you control have protection from each mana value among artifacts you control.
Partner (You can have two commanders if both have partner.)

Arsenal Thresher

As Arsenal Thresher enters, you may reveal any number of other artifact cards from your hand. Arsenal Thresher enters with a +1/+1 counter on it for each card revealed this way.

Sol Ring

Thopter Assembly

Flying
At the beginning of your upkeep, if you control no Thopters other than Thopter Assembly, return Thopter Assembly to its owner's hand and create five 1/1 colorless Thopter artifact creature tokens with flying.

Silas Renn, Seeker Adept

Deathtouch
Whenever Silas Renn, Seeker Adept deals combat damage to a player, choose target artifact card in your graveyard. You may cast that card this turn.
Partner (You can have two commanders if both have partner.)

Basalt Monolith

Basalt Monolith doesn't untap during your untap step.
{T}: Add {C}{C}{C}.
{3}: Untap Basalt Monolith.

Krark-Clan Ironworks

Time Sieve

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

Master Transmuter

{U}, {T}, Return an artifact you control to its owner's hand: You may put an artifact card from your hand onto the battlefield.

Mox Opal

Metalcraft — {T}: Add one mana of any color. Activate only if you control three or more artifacts.

Metalwork Colossus

This spell costs {X} less to cast, where X is the total mana value of noncreature artifacts you control.
Sacrifice two artifacts: Return Metalwork Colossus from your graveyard to your hand.

Dance of the Manse

Return up to X target artifact and/or non-Aura enchantment cards each with mana value X or less from your graveyard to the battlefield. If X is 6 or more, those permanents are 4/4 creatures in addition to their other types.

Oswald Fiddlebender

Magical Tinkering — {W}, {T}, Sacrifice an artifact: Search your library for an artifact card with mana value equal to 1 plus the sacrificed artifact's mana value, put it onto the battlefield, then shuffle. Activate only as a sorcery.