Fellwar Stone

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

Fire Diamond

Fire Diamond enters tapped.
{T}: Add {R}.

Arcane Signet

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

Rakdos Signet

Talisman of Indulgence

{T}: Add {C}.
{T}: Add {B} or {R}. Talisman of Indulgence deals 1 damage to you.

Blim, Comedic Genius

Flying
Whenever Blim, Comedic Genius deals combat damage to a player, that player gains control of target permanent you control. Then each player loses life and discards cards equal to the number of permanents they control but don't own.

Sol Ring

Charcoal Diamond

Charcoal Diamond enters tapped.
{T}: Add {B}.