Tailwind CSS - A utility-first CSS framework for rapidly building custom user interfaces.
Magic Playlist - Get the playlist of your dreams based on a song
Transformicons - Animated icons, symbols and buttons using SVG and CSS
Spotalike - Spotify playlist with similar songs, according to Last.fm
Animista - Create beautiful CSS animations in your browser
Playlist Machinery - Tools that help you create & organize your Spotify playlists