If I'm understanding what you want to do then yes, that is possible. Though what I'm going to tell you will not work if you have the product set to 'hidden',
To make a product available via URL only you must create a product that isn't part of a collection and that isn't linked anywhere on your website. Make sure the product doesn't fit into any of the rules of an automated collection you have set up, also double check that you don't have any links in your navigation or home page yourstorename.com/collections/all.
Some users might figure out that they can simply type go directly to yourstorename.com/collections/all and find the 'hidden' product in that list but that might be ok, depending on the goal of this tactic.