Thundersteel Colossus

Trample, haste
Crew 2 (Tap any number of creatures you control with total power 2 or more: This Vehicle becomes an artifact creature until end of turn.)

Darksteel Forge

Artifacts you control have indestructible. (Effects that say "destroy" don't destroy them. Artifact creatures with indestructible can't be destroyed by damage.)

Steel Hellkite

Flying
{2}: This creature gets +1/+0 until end of turn.
{X}: Destroy each nonland permanent with mana value X whose controller was dealt combat damage by this creature this turn. Activate only once each turn.

Darksteel Colossus

Trample (This creature can deal excess combat damage to the player or planeswalker it's attacking.)
Indestructible (Damage and effects that say "destroy" don't destroy this creature.)
If Darksteel Colossus would be put into a graveyard from anywhere, reveal Darksteel Colossus and shuffle it into its owner's library instead.

Swiftfoot Boots

Equipped creature has hexproof and haste. (It can't be the target of spells or abilities your opponents control. It can attack and {T} no matter when it came under your control.)
Equip {1} ({1}: Attach to target creature you control. Equip only as a sorcery.)

Myr Galvanizer

Other Myr creatures you control get +1/+1.
{1}, {T}: Untap each other Myr you control.

Loxodon Warhammer

Equipped creature gets +3/+0 and has trample and lifelink.
Equip {3}

Darksteel Relic

Indestructible (Effects that say "destroy" don't destroy this artifact.)

Mimic

{T}, Sacrifice Mimic: Add one mana of any color.
{2}: Mimic becomes a Shapeshifter artifact creature with base power and toughness 3/3 until end of turn.

Thran Dynamo

Alloy Myr

Colossus of Akros

Defender, indestructible
{10}: Monstrosity 10. (If this creature isn't monstrous, put ten +1/+1 counters on it and it becomes monstrous.)
As long as Colossus of Akros is monstrous, it has trample and can attack as though it didn't have defender.

Worn Powerstone

Worn Powerstone enters tapped.
{T}: Add {C}{C}.

Darksteel Myr

Indestructible (Damage and effects that say "destroy" don't destroy this creature. If its toughness is 0 or less, it's still put into its owner's graveyard.)

Mind Stone

{T}: Add {C}.
{1}, {T}, Sacrifice Mind Stone: Draw a card.

Argentum Armor

Equipped creature gets +6/+6.
Whenever equipped creature attacks, destroy target permanent.
Equip {6}

Darksteel Citadel

Colossus of Sardia

Trample (This creature can deal excess combat damage to the player or planeswalker it's attacking.)
Colossus of Sardia doesn't untap during your untap step.
{9}: Untap Colossus of Sardia. Activate only during your upkeep.

Darksteel Gargoyle

Flying
Indestructible (Damage and effects that say "destroy" don't destroy this creature.)

Crumbling Colossus

Trample (This creature can deal excess combat damage to the player or planeswalker it's attacking.)
When Crumbling Colossus attacks, sacrifice it at end of combat.

Colossus Hammer

Equipped creature gets +10/+10 and loses flying.
Equip {8} ({8}: Attach to target creature you control. Equip only as a sorcery.)

Steel Overseer

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

Commander's Sphere

{T}: Add one mana of any color in your commander's color identity.
Sacrifice Commander's Sphere: Draw a card.

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.

Forsaken Monument

Colorless creatures you control get +2/+2.
Whenever you tap a permanent for {C}, add an additional {C}.
Whenever you cast a colorless spell, you gain 2 life.

Traxos, Scourge of Kroog

Trample
Traxos, Scourge of Kroog enters tapped and doesn't untap during your untap step.
Whenever you cast a historic spell, untap Traxos. (Artifacts, legendaries, and Sagas are historic.)

Wastes

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.

Myr Enforcer

Affinity for artifacts (This spell costs {1} less to cast for each artifact you control.)

Sol Ring

Myriad Construct

Kicker {3}
If Myriad Construct was kicked, it enters with a +1/+1 counter on it for each nonbasic land your opponents control.
When Myriad Construct becomes the target of a spell, sacrifice it and create a number of 1/1 colorless Construct artifact creature tokens equal to its power.

Armory Automaton

Whenever Armory Automaton enters or attacks, you may attach any number of target Equipment to it. (Control of the Equipment doesn't change.)

Darksteel Monolith

Indestructible
Once each turn, you may pay {0} rather than pay the mana cost for a colorless spell you cast from your hand.

Darksteel Juggernaut

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