If you have them, consider adding any of these cards in place of some of the less-efficient dual lands or even basic Swamps or Plains: Shadowy Backstreet, Concealed Courtyard, Isolated Chapel, Brightclimb Pathway/Grimclimb Pathway, Godless Shrine
First of all, when I say free, I speak about the mana used to cast them , so I'm still allowed to pay other costs, like discarding cards, sacrificing creatures, or paying life
What this means is when you have it enter the battlefield, you get a ton of Treasure tokens since it adds up the total number of all artifacts and enchantments across all your opponents
For example, if you cast a copy of Shock for two mana, and a copy of Three Steps Ahead for the max five mana, your elemental will be a 5/5