Arcane Signet

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

Island

Plains

Sol Ring

Baleful Strix

Flying, deathtouch
When this creature enters, draw a card.

Urza, Chief Artificer

Affinity for artifact creatures (This spell costs {1} less to cast for each artifact creature you control.)
Artifact creatures you control have menace.
At the beginning of your end step, create a 0/0 colorless Construct artifact creature token with "This token gets +1/+1 for each artifact you control."