WooCommerce already comes with everything you need to sell physical and digital products. Thanks to Wootomation, you can turn you store a whole lot smarter. It uses machine learning that analyzes orders to recommend the best products to your customers. It is trained with your sales, so your store gets smarter over time.
This plugin lets you choose how many items you want to show under your products. You have the option to exclude out of stock products while including those that are back-ordered. Since this plugin uses your own data for recommendations, it can help significantly increase your chances of making more sales.