WooCommerce Sort By Stock is a relatively simple plugin. It does one thing and one thing only: allows you to sort by stock amount in WooCommerce.
Upon activation of this plugin, you will be able to sort products by the amount of stock remaining on your WooCommerce product dashboard page. Simply click on the Stock admin column to arrange by ascending or descending.
If sorting in ascending order, out of stock items will be shown first, followed by in stock but inventory not managed (no stock amount number), and finally showing in stock items which have a stock amount number, starting with 1 and increasing.
If sorting in descending order, will provide the opposite, starting with items with the largest amount of stock, moving down to out of stock.