Identifying: Picard (I think) by musicbrainz
Organizing and keeping track: Lidarr
There are alternatives to lidarr but that’s what I did for my ~300 files.
Picard matches by current metadata and to some extend by acoustic ID (similar to shazam).
Still better to review files before commiting the metadata (album, year, version, miss matched releases similar releases in name by cover bands or release name etc.)
For downloading more: I had great success with scarce releases (rare touhou songs) on soulseek.