Maybe this isn't a thing anymore or maybe I just cannot find it, but there used to be a site feature that would list ALL of your owned items (collections, shop stuff, wardrobe, everything) by what their current sP value was. Is there still any way of seeing this?

Unfortunately not :c It was disabled several years ago because it was too heavy on the servers

I figured there was a chance that was the case! It was so convenient to figure out what hidden gems were rotting in your account. Thank you for the speedy answer!

If you are not looking for total-worth just for kicks and are trying to find things to sell, there is a solution. The fansite Subetalodge allows you to make collections and then sort them