Arcane Signet
Artifact
: Add one mana of any color in your commander's color identity.
Dozens of empires lie dead and buried in the Broken Lands. But on Amonkhet, dead does not mean gone.
Michael Phillippi
Rulings
If your commander is a card that has no colors in its color identity, Arcane Signet's ability produces no mana. It doesn't produce {C}.
(wotc • 2020-11-10)
If you don't have a commander, Arcane Signet's ability produces no mana.
(wotc • 2020-11-10)
If you have two commanders, the ability adds one mana of any color in their combined color identities.
(wotc • 2020-11-10)
Rulings
If your commander is a card that has no colors in its color identity, Arcane Signet's ability produces no mana. It doesn't produce {C}.
(wotc • 2020-11-10)
If you don't have a commander, Arcane Signet's ability produces no mana.
(wotc • 2020-11-10)
If you have two commanders, the ability adds one mana of any color in their combined color identities.
(wotc • 2020-11-10)