Commerce Catalogs provides four out-of-the-box Product types: Simple, Grouped, Virtual and Diagram.
Simple Product: Any physical product for which inventory is tracked.
Grouped Product: Two or more Products from the Catalog that are packaged together and sold as a single item. Grouped Products are tracked in your inventory and can contain Simple Products, other Grouped Products, or Virtual Products.
Virtual Products: Any non-tangible Product, such as music files, electronic publications, services, and warranties.
Shop by Diagram: These are component parts belonging to a Bill of Materials (BOM) diagram that reference products in the store.