Maz Koshia, The Builder

: Play with the top card of your library revealed. If it's a guardian card, you may pay 3. if you do, exile it and make a Scrap artifact token
-2: Exile a guardian card from your graveyard with a repair counter on it
-3: Return a guardian card with a repair counter on it from exile to the battlefield. put a +1 +1 counter on it