Arcane Signet

• WWizards of the Coast2020-11-10
  Official Ruling
  If you have two commanders, the ability adds one mana of any color in their combined color identities.
• WWizards of the Coast2020-11-10
  Official Ruling
  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 .
• WWizards of the Coast2020-11-10
  Official Ruling
  If you don't have a commander, Arcane Signet's ability produces no mana.

Rulings via Scryfall