There aren't any. If you grow food, you're essential. If you ship food, you're essential. If you fix the trucks that ship food, you're essential. If you fix the air conditioner in the auto shop that fixes the trucks that ship food, you're essential. If you make screws for the air conditioner that gets installed in that auto shop, you're essential.
Read the shutdown orders. They enumerate essential industries, and the list of them is incredibly broad. In Washington state (Which has one of first, and furthest reaching shutdown orders), if you make literally anything that the military uses... You're essential. The list is incredibly broad.
These disruptions are caused directly by the virus getting people sick, and taking them out of work (And their workplaces, until people can get tested, and their workspace can be sanitized) - not the shutdown.
The shutdown actually serves to keep these facilities open, because it has reduced the virus's spread through the population.