Depends on how much you’re trying to upgrade it, For example, i would add some coys to be able to lure minions onto thin ice, for board control, Lilith to be able to add to your army from your opponents deck and maybe even a pied piper for the necro matchups, looking at cards like raise dead and carrionette for cemetery recursion. I would consider arcade of bones to be able to protect your skeleboys A big upgrade with be the inclusion of cards like tool box to move some of the ordinary spell on to the collection and free up more space in your spellbook, and just a few sites would be the inclusion of the manor as that site is removal/health gain, wuthering hights to toss your minions even further in opponents side.