Playlist Machinery - Tools that help you create & organize your Spotify playlists
beaTunes - Smart software for library management, music analysis, and playlist creation. For Windows and macOS.
Playmoss - Create playlists from YouTube, Vimeo and SoundCloud
KeyFinder - Key estimation software for DJs
Audioship - Upload audio to YouTube or Facebook
foo_bpm - A component for calculating the BPMs (beats per minute) of any tracks in Foobar2000.