Iron Myr

Myr Propagator

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

Plains

Myr Galvanizer

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

Palladium Myr

Mountain

Origin Spellbomb

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

Gold Myr

Myr Turbine

{T}: Create a 1/1 colorless Myr artifact creature token.
{T}, Tap five untapped Myr you control: Search your library for a Myr creature card, put it onto the battlefield, then shuffle.

Teetering Peaks

Teetering Peaks enters the battlefield tapped.
When Teetering Peaks enters the battlefield, target creature gets +2/+0 until end of turn.
{T}: Add {R}.

Myrsmith

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

Inventors' Fair

At the beginning of your upkeep, if you control three or more artifacts, you gain 1 life.
{T}: Add {C}.
{4}, {T}, Sacrifice Inventors' Fair: Search your library for an artifact card, reveal it, put it into your hand, then shuffle. Activate only if you control three or more artifacts.

Serum Tank

Whenever Serum Tank or another artifact enters the battlefield, put a charge counter on Serum Tank.
{3}, {T}, Remove a charge counter from Serum Tank: Draw a card.

Master's Call

Create two 1/1 colorless Myr artifact creature tokens.

Myr Sire

When Myr Sire dies, create a 1/1 colorless Phyrexian Myr artifact creature token.

Sejiri Steppe

Sejiri Steppe enters the battlefield tapped.
When Sejiri Steppe enters the battlefield, target creature you control gains protection from the color of your choice until end of turn.
{T}: Add {W}.

Smoldering Spires

Smoldering Spires enters the battlefield tapped.
When Smoldering Spires enters the battlefield, target creature can't block this turn.
{T}: Add {R}.

Fireball

This spell costs {1} more to cast for each target beyond the first.
Fireball deals X damage divided evenly, rounded down, among any number of targets.

Myr Battlesphere

When Myr Battlesphere enters the battlefield, 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.