Tenacity is an easy-to-use, cross-platform multi-track audio editor / recorder for Windows, macOS, Linux and other operating systems and is developed by a group of volunteers as open-source software.

Muine is an innovative music player, featuring a simple, intuitive interface. It is designed to allow users to easily construct a playlist from albums and/or single songs. Its goal is to be simply a music player, not to become a robust music management application. This doesn’t mean Muine has no features! Some feature highlights:
Muine is targeted at the GNOME desktop and uses GTK+ for the interface. Most of the code is written in C#, with some additions/bindings/glue in plain C. Muine was originally written by Jorn Baayen, but now maintained mostly by others.
github.com/mickeyr/Muine
gitlab.gnome.org/Archive/muine
en.wikipedia.org/wiki/Muine
manpages.org/muine
This is a component for the foobar2000 audio player, which provides a skinnable overlay UI.

theqwertiest.github.io/dotnet_title_bar
hydrogenaud.io/index.php?topic=121673
The Daphile is the heart of a digital music system. Its primary focus is in storage and playback of your digital music library. It enables the best possible audio quality and future-proof flexibility by providing plug&play support for USB connected digital-to-analog converters (DAC). You can easily setup a multi-zone system just by connecting another USB DAC for each zone.
Daphile is based on the open source Squeezebox Server, Squeezelite and Linux.
Since Daphile is used and configured completely via the web interface the user is not required to have any Linux skills.

PCM-DSD Converter is a program that converts a PCM WAV format sound source to DSD DSDIFF format. You can convert from PCM 16bit ~ 64bit Float / 44.1 ~ 768kHz to DSD16-DSD2048.
Adds and fixes music metadata and adds album art.
VintageRadio is a GUI front-end for the fm command-line application included with fmtools <http://benpfaff.org/fmtools>. It is written in [incr Tcl/Tk], an object-oriented extension package for Tcl/Tk. VintageRadio is not part of fmtools.

This project provides an open source MacOS v10.14, v10.15, v11.6 (Mojave, Catalina, Big Sur) compatible CoreMIDI 64 bit device driver for M-Audio’s MIDISPORT range of USB MIDI interfaces. This driver supports the following devices:
Other devices which are compatible may also work, although presently, these are the only ones which have been tested.
github.com/leighsmith/midisport-macos
sourceforge.net/projects/midisport-macos
Transform an album image into a video with songs tracks.
Select your favorite artist’s albums or your own picture with songs or sounds effects and transform it into a video with audio tracks that you can upload to YouTube.
wrk2mid is a command line utility for translating WRK (Cakewalk) files into MID (standard MIDI files). This project depends on Qt and Drumstick libraries.
Scrobble from anything including video streaming apps, less known audio players or even a song playing in your IM app. (if they send audio metadata to the Android system)

github.com/kawaiiDango/pScrobbler
play.google.com/store/apps/details?id=com.arn.scrobble