You do realize this is a bit of fun, right?
Yes, I think if you had to name one brand that was most famous that came from PA, it would be Hershey. Not that that company is the most dominant one or biggest in the state. Just that it is a recognizable brand from the Commonwealth.
Keeping in mind that Heinz is associated with Pittsburgh and it would tick off the people from the eastern part of the state if you picked a Pittsburgh brand. (And vice versa for a Philly brand.)
Everyone can agree on Hershey. Neutral turf. Center of state.
How about coal for PA? Or oil? Or, is that too 19th century?
Cream cheese for Philadelphia.