Cavern of Souls

As Cavern of Souls enters the battlefield, choose a creature type. {T}: Add {1} to your mana pool. {T}: Add one mana of any color to your mana pool. Spend this mana only to cast a creature spell of the chosen type, and that spell can't be countered.

Chief Engineer

Artifact spells you cast have convoke. (Your creatures can help cast those spells. Each creature you tap while casting an artifact spell pays for {1} or one mana of that creature's color.)

Blinkmoth Nexus

{T}: Add {1} to your mana pool. {1}: Blinkmoth Nexus becomes a 1/1 Blinkmoth artifact creature with flying until end of turn. It's still a land. {1}, {T}: Target Blinkmoth creature gets +1/+1 until end of turn.

Signal Pest

Battle cry (Whenever this creature attacks, each other attacking creature gets +1/+0 until end of turn.) Signal Pest can't be blocked except by creatures with flying or reach.

Judge's Familiar

Flying Sacrifice Judge's Familiar: Counter target instant or sorcery spell unless its controller pays {1}.

Unified Will

Counter target spell if you control more creatures than that spell's controller.

Oboro, Palace in the Clouds

{T}: Add {U} to your mana pool. {1}: Return Oboro, Palace in the Clouds to its owner's hand.

Grand Architect

Other blue creatures you control get +1/+1. {U}: Target artifact creature becomes blue until end of turn. Tap an untapped blue creature you control: Add {2} to your mana pool. Spend this mana only to cast artifact spells or activate abilities of artifacts.

Etherium Sculptor

Artifact spells you play cost {1} less to play.

Master of Etherium

Master of Etherium's power and toughness are each equal to the number of artifacts you control. Other artifact creatures you control get +1/+1.

Lodestone Golem

Nonartifact spells cost {1} more to cast.

Mausoleum Wanderer

Smuggler's Copter

Walking Ballista

Throne of the God-Pharaoh