Shrine of Loyal Legions

At the beginning of your upkeep and whenever you cast a white spell, put a charge counter on this artifact.
{3}, {T}, Sacrifice this artifact: Create a 1/1 colorless Phyrexian Myr artifact creature token for each charge counter on this artifact.

Myr Reservoir

{T}: Add {C}{C}. Spend this mana only to cast Myr spells or activate abilities of Myr.
{3}, {T}: Return target Myr card from your graveyard to your hand.

Hovermyr

Myr Galvanizer

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

Myr Propagator

{3}, {T}: Create a token that's a copy of this creature.