Gut, True Soul Zealot

Whenever you attack, you may sacrifice another creature or an artifact. If you do, create a 4/1 black Skeleton creature token with menace that's tapped and attacking. (It can't be blocked except by two or more creatures.)
Choose a Background (You can have a Background as a second commander.)

Feedback Bolt

Feedback Bolt deals damage to target player or planeswalker equal to the number of artifacts you control.

Warden of the Inner Sky

As long as this creature has three or more counters on it, it has flying and vigilance.
Tap three untapped artifacts and/or creatures you control: Put a +1/+1 counter on this creature. Scry 1. Activate only as a sorcery.

Leonin Elder

Whenever an artifact enters, you may gain 1 life.

Helm of Awakening

Caparocti Sunborn

Whenever Caparocti Sunborn attacks, you may tap two untapped artifacts and/or creatures you control. If you do, discover 3. (Exile cards from the top of your library until you exile a nonland card with mana value 3 or less. Cast it without paying its mana cost or put it into your hand. Put the rest on the bottom in a random order.)

Veil of Assimilation

Whenever this artifact or another artifact you control enters, target creature you control gets +1/+1 and gains vigilance until end of turn.

Losheel, Clockwork Scholar

Prevent all combat damage that would be dealt to attacking artifact creatures you control.
Whenever one or more artifact creatures you control enter, draw a card. This ability triggers only once each turn.

Indomitable Archangel

Flying
Metalcraft — Artifacts you control have shroud as long as you control three or more artifacts. (An artifact with shroud can't be the target of spells or abilities.)

Steel Overseer

{T}: Put a +1/+1 counter on each artifact creature you control.

Reckless Fireweaver

Whenever an artifact you control enters, this creature deals 1 damage to each opponent.

Ingenious Artillerist

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

Thopter Architect

Whenever an artifact you control enters, target creature gains flying until end of turn.

Barracks of the Thousand

(Transforms from Thousand Moons Smithy.)
{T}: Add {W}.
Whenever you cast an artifact or creature spell using mana produced by Barracks of the Thousand, create a white Gnome Soldier artifact creature token with "This token's power and toughness are each equal to the number of artifacts and/or creatures you control."

Thousand Moons Smithy

When Thousand Moons Smithy enters, create a white Gnome Soldier artifact creature token with "This token's power and toughness are each equal to the number of artifacts and/or creatures you control."
At the beginning of your first main phase, you may tap five untapped artifacts and/or creatures you control. If you do, transform Thousand Moons Smithy.

Thousand Moons Smithy // Barracks of the Thousand

Compass Gnome

When this creature enters, you may search your library for a basic land card or Cave card, reveal it, then shuffle and put that card on top.

Envoy of Okinec Ahau

{4}{W}: Create a 1/1 colorless Gnome artifact creature token.

Metrognome

When a spell or ability an opponent controls causes you to discard this card, create four 1/1 colorless Gnome artifact creature tokens.
{4}, {T}: Create a 1/1 colorless Gnome artifact creature token.

Acolyte Hybrid

Heavy Rock Cutter — Whenever this creature attacks, destroy up to one target artifact. If an artifact is destroyed this way, its controller draws a card.

Guardian of the Great Door

As an additional cost to cast this spell, tap four untapped artifacts, creatures, and/or lands you control.
Flying

Tinker's Tote

When this artifact enters, create two 1/1 colorless Gnome artifact creature tokens.
{W}, Sacrifice this artifact: You gain 3 life.

Hellkite Igniter

Flying, haste
{1}{R}: This creature gets +X/+0 until end of turn, where X is the number of artifacts you control.

Unwinding Clock

Untap all artifacts you control during each other player's untap step.

Adaptive Gemguard

Tap two untapped artifacts and/or creatures you control: Put a +1/+1 counter on this creature. Activate only as a sorcery.

Darksteel Juggernaut

Indestructible
Darksteel Juggernaut's power and toughness are each equal to the number of artifacts you control.
This creature attacks each combat if able.

Dispatch

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

Mandible Justiciar

Lifelink
Whenever another artifact you control enters, this creature gets +1/+1 until end of turn.

Ajani's Welcome

Whenever a creature you control enters, you gain 1 life.

Dragonspark Reactor

Whenever this artifact or another artifact you control enters, put a charge counter on this artifact.
{4}, Sacrifice this artifact: It deals damage equal to the number of charge counters on it to target player and that much damage to up to one target creature.

Anim Pakal, Thousandth Moon

Whenever you attack with one or more non-Gnome creatures, put a +1/+1 counter on Anim Pakal, then create X 1/1 colorless Gnome artifact creature tokens that are tapped and attacking, where X is the number of +1/+1 counters on Anim Pakal.

Plated Onslaught

Affinity for artifacts (This spell costs {1} less to cast for each artifact you control.)
Creatures you control get +2/+1 until end of turn.

Oltec Cloud Guard

Flying
When this creature enters, create a 1/1 colorless Gnome artifact creature token.

Leonin Abunas

Artifacts you control have hexproof. (They can't be the targets of spells or abilities your opponents control.)

Illustrious Wanderglyph

Ascend (If you control ten or more permanents, you get the city's blessing for the rest of the game.)
Other artifact creatures you control get +2/+2 as long as you have the city's blessing.
At the beginning of each upkeep, create a 1/1 colorless Gnome artifact creature token.

Sentinel Sarah Lyons

Haste
As long as an artifact entered the battlefield under your control this turn, creatures you control get +2/+2.
Battalion — Whenever Sentinel Sarah Lyons and at least two other creatures attack, Sentinel Sarah Lyons deals damage equal to the number of artifacts you control to target player.

Etched Champion

Metalcraft — This creature has protection from each color as long as you control three or more artifacts.

Bronze Guardian

Double strike
Ward {2} (Whenever this creature becomes the target of a spell or ability an opponent controls, counter it unless that player pays {2}.)
Other artifacts you control have ward {2}.
Bronze Guardian's power is equal to the number of artifacts you control.

Cosmium Kiln

When this artifact enters, create two 1/1 colorless Gnome artifact creature tokens.
Creatures you control get +1/+1.

Clay-Fired Bricks

When this artifact enters, search your library for a basic Plains card, reveal it, put it into your hand, then shuffle. You gain 2 life.
Craft with artifact {5}{W}{W} ({5}{W}{W}, 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.)

Clay-Fired Bricks // Cosmium Kiln

Daretti, Scrap Savant

+2: Discard up to two cards, then draw that many cards.
−2: Sacrifice an artifact. If you do, return target artifact card from your graveyard to the battlefield.
−10: You get an emblem with "Whenever an artifact is put into your graveyard from the battlefield, return that card to the battlefield at the beginning of the next end step."
Daretti, Scrap Savant can be your commander.

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

Hedron Detonator

Whenever an artifact you control enters, this creature deals 1 damage to target opponent.
{T}, Sacrifice two artifacts: Exile the top card of your library. You may play that card this turn.

Grinding Station

{T}, Sacrifice an artifact: Target player mills three cards.
Whenever an artifact enters, you may untap this artifact.

Fathom Fleet Swordjack

Whenever this creature attacks, it deals damage to the player or planeswalker it's attacking equal to the number of artifacts you control.
Encore {5}{R} ({5}{R}, Exile this card from your graveyard: For each opponent, create a token copy that attacks that opponent this turn if able. They gain haste. Sacrifice them at the beginning of the next end step. Activate only as a sorcery.)

Arcane Signet

{T}: Add one mana of any color in your commander's color identity.

Foundry Inspector

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

Welding Sparks

Welding Sparks deals X damage to target creature, where X is 3 plus the number of artifacts you control.

Hellkite Tyrant

Flying, trample
Whenever Hellkite Tyrant deals combat damage to a player, gain control of all artifacts that player controls.
At the beginning of your upkeep, if you control twenty or more artifacts, you win the game.

Dispense Justice

Target player sacrifices an attacking creature of their choice.
Metalcraft — That player sacrifices two attacking creatures of their choice instead if you control three or more artifacts.

Nettlecyst

Living weapon (When this Equipment enters, create a 0/0 black Phyrexian Germ creature token, then attach this to it.)
Equipped creature gets +1/+1 for each artifact and/or enchantment you control.
Equip {2}

Jor Kadeen, the Prevailer

First strike
Metalcraft — Creatures you control get +3/+0 as long as you control three or more artifacts.

Attentive Sunscribe

Whenever this creature becomes tapped, scry 1. (Look at the top card of your library. You may put that card on the bottom.)

Alibou, Ancient Witness

Other artifact creatures you control have haste.
Whenever one or more artifact creatures you control attack, Alibou deals X damage to any target and you scry X, where X is the number of tapped artifacts you control.

Threefold Thunderhulk

This creature enters with three +1/+1 counters on it.
Whenever this creature enters or attacks, create a number of 1/1 colorless Gnome artifact creature tokens equal to its power.
{2}, Sacrifice another artifact: Put a +1/+1 counter on this creature.

Platoon Dispenser

At the beginning of your end step, if you control two or more other creatures, draw a card.
{3}{W}: Create a 1/1 colorless Soldier artifact creature token.
Unearth {2}{W}{W}

Sol Ring

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 this artifact 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 this artifact if you control four or more artifacts.