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