In the Trenches

Creatures you control get +1/+1.
{5}{W}: Exile target nonland permanent you don't control until In the Trenches leaves the battlefield. Activate only as a sorcery and only once.

Great Desert Prospector

When Great Desert Prospector enters, create a tapped Powerstone token for each other creature you control. (They're artifacts with "{T}: Add {C}. This mana can't be spent to cast a nonartifact spell.")

Meticulous Excavation

{2}{W}: Return target permanent you control to its owner's hand. If it has unearth, instead exile it, then return that card to its owner's hand. Activate only during your turn.

Myrel, Shield of Argive

During your turn, your opponents can't cast spells or activate abilities of artifacts, creatures, or enchantments.
Whenever Myrel, Shield of Argive attacks, create X 1/1 colorless Soldier artifact creature tokens, where X is the number of Soldiers you control.

Calamity's Wake

Exile all graveyards. Players can't cast noncreature spells this turn. Exile Calamity's Wake.