TubeLister - Generate a YouTube playlist from your opened tabs.
you-tldr - Get the tldr of any YouTube video in seconds
OrganizeTube - Create video playlists from Youtube, Vimeo and other sources
Vidlis - Create music playlists from YouTube videos.
SliceTube - The Fast and Modern way to cut and download YouTube videos
Playmoss - Create playlists from YouTube, Vimeo and SoundCloud