Arcane Signet

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

City of Brass

Whenever City of Brass becomes tapped, it deals 1 damage to you.
{T}: Add one mana of any color.

{T}, Pay 1 life: Add one mana of any color.

Lands you control have "{T}: Add one mana of any color."
{T}: Add one mana of any color.

{T}: Add one mana of any color that a land an opponent controls could produce.

{T}: Add one mana of any color in your commander's color identity.
Sacrifice Commander's Sphere: Draw a card.

Rupture Spire enters tapped.
When Rupture Spire enters, sacrifice it unless you pay {1}.
{T}: Add one mana of any color.