Command Tower

{T}: Add one mana of any color in your commander's color identity.

Rhystic Study

Whenever an opponent casts a spell, you may draw a card unless that player pays {1}.

{T}, Sacrifice this land: Search your library for a basic land card, put it onto the battlefield tapped, then shuffle.

When Circuit Mender enters, you gain 2 life.
When Circuit Mender leaves the battlefield, draw a card.

{T}, Sacrifice Black Lotus: Add three mana of any one color.