Arcane Signet

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

Inquisitor Greyfax

Vigilance
Unquestionable Wisdom — Other creatures you control get +1/+0 and have vigilance.
Hunt for Heresy — {1}, {T}: Tap target creature an opponent controls. Investigate. (Create a Clue token. It's an artifact with "{2}, Sacrifice this artifact: Draw a card.")

Sol Ring

Commander's Sphere

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