Arcbound Crusher

Trample
Whenever another artifact enters, put a +1/+1 counter on Arcbound Crusher.
Modular 1 (This creature enters with a +1/+1 counter on it. When it dies, you may put its +1/+1 counters on target artifact creature.)

Scrapyard Recombiner

Modular 2 (This creature enters with two +1/+1 counters on it. When it dies, you may put its +1/+1 counters on target artifact creature.)
{T}, Sacrifice an artifact: Search your library for a Construct card, reveal it, put it into your hand, then shuffle.

Liberator, Urza's Battlethopter

Flash
Flying
You may cast colorless spells and artifact spells as though they had flash.
Whenever you cast a spell, if the amount of mana spent to cast that spell is greater than Liberator, Urza's Battlethopter's power, put a +1/+1 counter on Liberator.

Arcbound Tracker

Menace
Modular 2 (This creature enters with two +1/+1 counters on it. When it dies, you may put its +1/+1 counters on target artifact creature.)
Whenever you cast a spell other than your first spell each turn, put a +1/+1 counter on Arcbound Tracker.

Myr Retriever

When Myr Retriever dies, return another target artifact card from your graveyard to your hand.

Canoptek Spyder

Flying
Fabricator Claw Array — Whenever another nontoken artifact creature or Vehicle you control enters, draw a card.

Forgotten Ancient

Whenever a player casts a spell, you may put a +1/+1 counter on Forgotten Ancient.
At the beginning of your upkeep, you may move any number of +1/+1 counters from Forgotten Ancient onto other creatures.

Pia's Revolution

Whenever a nontoken artifact is put into your graveyard from the battlefield, return that card to your hand unless target opponent has Pia's Revolution deal 3 damage to them.

Evolution Sage

Landfall — Whenever a land you control enters, proliferate. (Choose any number of permanents and/or players, then give each another counter of each kind already there.)

Meria, Scholar of Antiquity

Tap an untapped nontoken artifact you control: Add {G}.
Tap two untapped nontoken artifacts you control: Exile the top card of your library. You may play it this turn.

Stonecoil Serpent

Reach, trample, protection from multicolored
Stonecoil Serpent enters with X +1/+1 counters on it.

Grumgully, the Generous

Each other non-Human creature you control enters with an additional +1/+1 counter on it.

Reckless Handling

Search your library for an artifact card, reveal it, put it into your hand, shuffle, then discard a card at random. If an artifact card was discarded this way, Reckless Handling deals 2 damage to each opponent.

Invigorating Hot Spring

Invigorating Hot Spring enters with four +1/+1 counters on it.
Modified creatures you control have haste. (Equipment, Auras you control, and counters are modifications.)
Remove a +1/+1 counter from Invigorating Hot Spring: Put a +1/+1 counter on target creature you control. Activate only as a sorcery and only once each turn.

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.

Foundry Inspector

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

Arcbound Overseer

At the beginning of your upkeep, put a +1/+1 counter on each creature you control with modular.
Modular 6 (This creature enters with six +1/+1 counters on it. When it dies, you may put its +1/+1 counters on target artifact creature.)

Verdurous Gearhulk

Trample
When Verdurous Gearhulk enters, distribute four +1/+1 counters among any number of target creatures you control.

Scrap Trawler

Whenever Scrap Trawler or another artifact you control is put into a graveyard from the battlefield, return to your hand target artifact card in your graveyard with lesser mana value.

Triskelion

Triskelion enters with three +1/+1 counters on it.
Remove a +1/+1 counter from Triskelion: It deals 1 damage to any target.

Steel Overseer

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

Inspiring Call

Draw a card for each creature you control with a +1/+1 counter on it. Those creatures gain indestructible until end of turn. (Damage and effects that say "destroy" don't destroy them.)