Brain.fm - Music designed for the brain to enhance focus, relaxation, meditation, naps and sleep within 10 - 15 minutes of use.
Magic Playlist - Get the playlist of your dreams based on a song
Tinnire - Generative music for productive work from home
Spotalike - Spotify playlist with similar songs, according to Last.fm
Noisli - Noisli is a fantastic background noise and color generator for working and relaxing. Online soothing ambient sounds like White noise, Rain and Coffee Shop.
Playlist Machinery - Tools that help you create & organize your Spotify playlists