For one , my KA!!!!!
Fat Daddio's turntable
Plastic and metal bench scrapers (plastic for incredible smoothing of butter cream, and metal for quick clean up)
Straight and offset spatulas
Nesting bowls for mise en place (like to have ingredients weighed and measured before making anything)
Arsenal of tips, couplers, and disposable pastry bags
large medium and small sifters
Americolor food colors
If I didn't have these things I think I would lose my mind.
What are your must have weapons of choice for mass cake production?