Snowflipper just works well in this deck. It prevents overdraw and it’s a good trigger for Plague of Flames, Defile, or Lordgodfrey.
My version also runs 2 soul infusions to prevent overdraw and it can also be used to try and reach that magic number you need for Defile or Godfrey to go off that one extra time if you need it. You can also get lucky from time to time and play it Zillax for extra healing.
other than that, it’s your basic Mecha’thun Warlock. In exchange for Guldan and high cost demons, it instead focuses on constant card draw. The constant card draw will almost always ensure that you have a strong board clear at all times.