What qualifies as a duplicate in your opinion?
See e.g. this thread on the problem if you rely only on the tags:
In Mp3tag you can load files from all over the place, not just one folder. And you can add further files and folders to the already loaded ones.
In MP3tag you can sort and filter.
If you need a program that also uses an acoustic fingerprint, try "Similarity" (can be found with your favourite internet search).