Myr Retriever

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

Adaptive Automaton

As Adaptive Automaton enters, choose a creature type.
Adaptive Automaton is the chosen type in addition to its other types.
Other creatures you control of the chosen type get +1/+1.

Myr Battlesphere

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

Myr Galvanizer

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

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 Propagator

{3}, {T}: Create a token that's a copy of Myr Propagator.

Dispatch

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

Roar of Reclamation

Each player returns all artifact cards from their graveyard to the battlefield.

Palladium Myr

Hovermyr

Gold Myr

Steel Overseer

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

Myr Superion

Spend only mana produced by creatures to cast this spell.