Program: Strawberry Music Player
License: Open Source/GPL 3.0
Description: Strawberry is a music player and music collection organizer for Linux, macOS and Windows. It is aimed at music collectors and audiophiles. Started in 2018, it is a fork and continuation of Clementine Music Player which last released in 2014. It is one of the only actively maintained, open-source, cross-platform music organizers targeting all 3 major PC platforms, and its niche features to support bit-perfect playback further increase its appeal for audiophiles.
This was also received favourably in a recent thread at https://portableapps.com/node/65213 but since the OP of that thread didn't follow through on submitting a request, I decided I would do it instead. It's a great app, I've used it for years, but nothing would make me happier than to be able to easily port it around with my music library, so I can keep everything all in one place.