WooCommerce Simple Auctions
With the WooCommerce Simple Auctions extension, you can create auctions from the frontend. The simple auction settings are added to the WooCommerce general settings form element. Just go to the product form you like to use for simple auctions or add the general settings form element to the form to access the settings
The WooCommerce Simple Auction plugin can be found here: https://codecanyon.net/item/woocommerce-simple-auctions-wordpress-auctions/6811382
You can predefine the simple auction product and hide all the options not needed for your auction product form. If you select product type hidden and select "Auction" as type all other product type specific options will be removed from the form. This will enable you to create an Auction product form with just the fields needed to create the auction product.