TubeLister - Generate a YouTube playlist from your opened tabs.
DiskyT - Youtube playlists done right
OrganizeTube - Create video playlists from Youtube, Vimeo and other sources
Playmoss - Create playlists from YouTube, Vimeo and SoundCloud
YouTube Vanced - Vanced is a modded version of YouTube with many features such as adblocking and background playback
Poolsuite™ - The super-summer music player