Emerald Medallion

Green spells you cast cost {1} less to cast.

Sol Ring

Deathtouch
Skip your draw step.
At the beginning of your upkeep, if you have fewer than seven cards in hand, draw cards equal to the difference.

Blue spells you cast cost {1} less to cast.

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

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

Black spells you cast cost {1} less to cast.

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

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