I like to suggest EasyTAG as being a good addition to PortableApps. I had thought the EasyTAG project was dead, but no, I just found out it has moved home and is still an active project. Can currently been seen here: https://wiki.gnome.org/Apps/EasyTAG There is a Windows installer version (so it's not just for Linux).
EasyTAG is freeware and license is "GNU General Public License". License guidelines can be seen at the bottom of the page here: https://gitlab.gnome.org/GNOME/easytag
I think this would be a good addition to PortableApps list of portables. EasyTAG is easy to use and a very good tagger.