Hi, Is there a plugin that will show customers additional products (add-on products) on checkout only? For example, a customer added a pair of boots in the cart, when they checkout additional products will show as an add-on (i.e bags). These add-on items can only be purchased as an add-on and NOT as an individual item. Thank you.
You actually need WooCommerce Product Bundles.
Provided either by WooCommerce or you can search for product bundle plugins on CodeCanyon.
You can set a product to be either sold only as part of a bundle or as a standalone or both and even control many, many other very practical things beyond that.
I don’t know if it is needed at all for you in case you can set the above mentioned options.
If yes, just check the description/documentation of the plugin you find if it is possible to set.