DiskyT - Youtube playlists done right
Parallel - Listen to music with friends over Spotify at the same time
OrganizeTube - Create video playlists from Youtube, Vimeo and other sources
Join My Playlist - Listen to music live together with your friends in Spotify.
Tuned Rocks📺 - Discover🔎 curated Youtube videos 24/7
TuneMeet - Chat with people who are listening to the same song