Mountain

Pia's Revolution

Whenever a nontoken artifact is put into your graveyard from the battlefield, return that card to your hand unless target opponent has Pia's Revolution deal 3 damage to them.

The Mycosynth Gardens

{T}: Add {C}.
{1}, {T}: Add one mana of any color.
{X}, {T}: The Mycosynth Gardens becomes a copy of target nontoken artifact you control with mana value X.

Scrap Mastery

Each player exiles all artifact cards from their graveyard, then sacrifices all artifacts they control, then puts all cards they exiled this way onto the battlefield.

Trash for Treasure

As an additional cost to cast this spell, sacrifice an artifact.
Return target artifact card from your graveyard to the battlefield.

Bosh, Iron Golem

Trample
{3}{R}, Sacrifice an artifact: Bosh, Iron Golem deals damage equal to the sacrificed artifact's mana value to any target.