Arcane Signet

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

Rogue's Passage

{T}: Add {C}.
{4}, {T}: Target creature can't be blocked this turn.

Sacrifice an artifact: Atog gets +2/+2 until end of turn.

Indestructible (Effects that say "destroy" don't destroy this artifact.)
{T}: Add one mana of any color.

Indestructible (Effects that say "destroy" don't destroy this artifact.)

Affinity for artifacts (This spell costs {1} less to cast for each artifact you control.)