Radios.YT - Listen to the best YouTube music livestreams for free, 24/7
CONV. - Convert YouTube video to MP3, GIF or MP4
YouTube Music - YouTube Music is a streaming app primarily designed for Android and iOS mobile devices. The app lets individuals search for music from their favorite artists, enjoy playlists, and access 30 million musical tracks.
Downie - Video download for OS X. Downie supports at this moment over 1,000 different sites.
CandyLists - Create interest based YouTube feeds
Yout - YouTube to Mp3 Converter