I'm building a web-based marketplace. Whenever a user really wants to sell an item, Let me have the ability to allow him to selects the merchandise from the standardized product catalog/database.

Can there be any openly available database that consists of the majority of the standardized items for example book game titles, electronics (e.g. "apple iphone 4 32GB"), home home appliances (e.g. "Whirlpool - 4. Cu. Foot. 10-Cycle Washer"), etc.?

Thanks

Here you go, Amazon's catalog, the nearest factor to "everything".