Jet Medallion

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

Commander's Sphere

{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 in your commander's color identity.

{T}, Sacrifice Jeweled Lotus: Add three mana of any one color. Spend this mana only to cast your commander.

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

Indestructible (Effects that say "destroy" don't destroy this artifact.)
{T}: Add one mana of any color.

At the beginning of your upkeep, flip a coin. If you lose the flip, Mana Crypt deals 3 damage to you.
{T}: Add {C}{C}.

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

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

{2}, {T}, Sacrifice Wayfarer's Bauble: Search your library for a basic land card, put that card onto the battlefield tapped, then shuffle.