Fellwar Stone

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

Azorius Signet

Mind Stone

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

Raff, Weatherlight Stalwart

Whenever you cast an instant or sorcery spell, you may tap two untapped creatures you control. If you do, draw a card.
{3}{W}{W}: Creatures you control get +1/+1 and gain vigilance until end of turn.

Arcane Signet

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