Urza, Lord Protector

Artifact, instant, and sorcery spells you cast cost {1} less to cast.
{7}: If you both own and control Urza, Lord Protector and an artifact named The Mightstone and Weakstone, exile them, then meld them into Urza, Planeswalker. Activate only as a sorcery.

Belisarius Cawl

Ultima Founding — {T}, Tap two untapped artifacts you control: Create a 2/2 white Astartes Warrior creature token with vigilance.
Master of Machines — {T}, Tap X untapped creatures you control: Look at the top X cards of your library. You may reveal an artifact card from among them and put it into your hand. Put the rest on the bottom of your library in a random order.