Fellwar Stone

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

Chiss-Goria, Forge Tyrant

Affinity for artifacts (This spell costs {1} less to cast for each artifact you control.)
Flying, haste
Whenever Chiss-Goria, Forge Tyrant attacks, exile the top five cards of your library. You may cast an artifact spell from among them this turn. If you do, it has affinity for artifacts.

Platinum Angel

Flying
You can't lose the game and your opponents can't win the game.

Commander's Sphere

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

Mountain

Wayfarer's Bauble

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