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.

You have no maximum hand size.
{T}: Add {C}.

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

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