Fellwar Stone

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

Arcane Signet

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

At the beginning of your upkeep, flip a coin. If you lose the flip, Mana Crypt deals 3 damage to you.
{T}: Add {C}{C}.

Moss Diamond enters tapped.
{T}: Add {G}.

Metalcraft — {T}: Add one mana of any color. Activate only if you control three or more artifacts.

{T}: Add {C}{C}. Ancient Tomb deals 2 damage to you.

Fire Diamond enters tapped.
{T}: Add {R}.