An organization called the National Motor Freight Traffic Association (NMFTA) publishes a list of freight class designations, codes, and subclasses for many frequently shipped items (https://classit.nmfta.org/). To view this list, you must pay a subscription fee. Learn more about freight classes from the experts at Koho for free on our freight classes pages.
Your freight cost is determined by a number of variables, such as how far your shipment needs to go, the freight class number, whether or not accessorials are needed, as well as fluctuating fuel costs and truck capacity.
No, not all commodities have freight subclasses, although many do.