Mechagoria, Artificer Savant

You may tap any number of untapped artifacts to pay for one mana in that artifact's color identity to pay for this spell's cost
When the second nontoken artifact enters the battlefield under your control on your turn, add {1} to your mana pool
When the second token artifact enters the battlefield under your control on your turn, create a treasure token
As long as you control 8 or more artifacts, Mechagoria, Artificer Savant is not a creature