TubeLister - Generate a YouTube playlist from your opened tabs.
Vidlis - Create music playlists from YouTube videos.
Playmoss - Create playlists from YouTube, Vimeo and SoundCloud
DiskyT - Youtube playlists done right
NewPipe - NewPipe is a lightweight YouTube front-end for Android.
JuniorTube - Curate YouTube playlists. Remotely push them to kids iPads.