A way to save posts, CPT’s, products as e.g. in cookies, user metadata, session or local storage. Then to call them up via an archive page.
This would require a button to add or remove from the list again.
Application e.g. for:
Yes! Ability to set and read cookies for popups. (so multiple popups can share the same cookie)
Also a condition to show/hide an element if cookie exists.