Build a directory of products that are no longer manufactured. This directory might include sections on toys, novelties, music items, household goods, clothing, novelties, furniture items, accessories, shoes, and so on. You could visit antique stores and interview owners about the most popular items. Maybe choose products in eras such as 1950s, 1960s, 1980s and keep an eye on what may be coming back into fashion.
The idea is to create