There should be a multi-book search option that includes searching for an author or a series, and the results would show us a list of shops that are the “best match” to the search query even if it doesn’t include every single book by that author or in that series.

For example, if I want to collect all the works by C. S. Lewis, he has dozens of books and essay collections, and adding every one of them to the search would be tedious and yield zero results. But I want to know which shops have the most number of his books for sale so I can start there with my bundles rather than searching title by title and hope I find a shop that has a lot of his books for sale.

Another option is if I want to collect all the books in a series. Let’s say I add every Harry Potter book to the multi-search tool but there are no shops selling all 7 books so I see no results. But if a shop is selling 6/7 books, that should show up at the top as a “best match” result so at least I can get the majority of the books in a bundle.