Commander's Sphere

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

Marble Diamond

Marble Diamond enters tapped.
{T}: Add {W}.

Whenever Théoden, King of Rohan or another Human you control enters, target creature gains double strike until end of turn.

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

{T}: Add {C}.
{1}, {T}, Sacrifice Mind Stone: Draw a card.

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