Fellwar Stone

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

Exotic Orchard

({T}: Add {R} or {G}.)
As this land enters, you may pay 2 life. If you don't, it enters tapped.

This artifact enters tapped.
{T}: Add {R}.

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

This artifact enters tapped.
{T}: Add {G}.

{T}: Add {C}.
{T}: Add {R} or {G}. This artifact deals 1 damage to you.

This land enters tapped unless you have two or more opponents.
{T}: Add {R} or {G}.

{T}: Add {C}.
{R/G}, {T}: Add {R}{R}, {R}{G}, or {G}{G}.