I’m not a huge fan of managing in general, therefore my answer might disappoint you: I use Calibre and my columns are restricted to title, author(s), and tags. Once in a while I make a backup . On my ebook reader (a Pocketbook) all ebooks are stored on a SD card, no folders. A new ebook is send to the reader by mail, moved from internal storage to SD card and then imported to Calibre.