Darksteel Sentinel

Flash (You may cast this spell any time you could cast an instant.)
Vigilance
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.)

Auriok Edgewright

Metalcraft — This creature has double strike as long as you control three or more artifacts.

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.)

Myr Galvanizer

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

Plains

Inspired Charge

Creatures you control get +2/+1 until end of turn.

Origin Spellbomb

{1}, {T}, Sacrifice this artifact: Create a 1/1 colorless Myr artifact creature token.
When this artifact is put into a graveyard from the battlefield, you may pay {W}. If you do, draw a card.

Razor Hippogriff

Flying
When this creature enters, return target artifact card from your graveyard to your hand. You gain life equal to that card's mana value.

Gold Myr

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.

Myrsmith

Whenever you cast an artifact spell, you may pay {1}. If you do, create a 1/1 colorless Myr artifact creature token.

Kemba's Skyguard

Flying
When this creature enters, you gain 2 life.

Revoke Existence

Perilous Myr

When this creature dies, it deals 2 damage to any target.

Seize the Initiative

Target creature gets +1/+1 and gains first strike until end of turn.

Myr Battlesphere

When this creature enters, create four 1/1 colorless Myr artifact creature tokens.
Whenever this creature attacks, you may tap X untapped Myr you control. If you do, this creature gets +X/+0 until end of turn and deals X damage to the player or planeswalker it's attacking.

Palladium Myr

Arrest

Enchant creature
Enchanted creature can't attack or block, and its activated abilities can't be activated.

Sunblast Angel

Flying
When this creature enters, destroy all tapped creatures.

Ghalma's Warden

Metalcraft — This creature gets +2/+2 as long as you control three or more artifacts.