Tuned Rocks📺 - Discover🔎 curated Youtube videos 24/7
Vidlis - Create music playlists from YouTube videos.
OrganizeTube - Create video playlists from Youtube, Vimeo and other sources
Playmoss - Create playlists from YouTube, Vimeo and SoundCloud
JuniorTube - Curate YouTube playlists. Remotely push them to kids iPads.
Quite a Playlist - Find deleted & private video details from YouTube playlists