An approved vendor list (AVL) is a listing of various types of suppliers and providers that a company has agreed meets its standards in terms of quality and price, and has authorized purchasing agents and others within the company structure to place orders with when and as required.long with companies, non-profit organizations and even governmental departments will also normally assemble a list of approved vendors to use for everything from stocking the vending machines in an employee break area to the purchase of high-priced equipment for use in a manufacturing operation.