reEmbed - Custom YouTube Video Player
TabFloater - Browser extension to use picture-in-picture with any website
Video Hub App - The fastest way to browse, search, and manage videos on your computer. Like YouTube for videos on your computer!
Vid Repeat - Loop YouTube videos for X minutes or for X times. Loop a full video, or only a selected part, add a delay between the loops, and share the loop with your friends.
riv.yt - A minimalist way to view and share YouTube videos
mps-youtube - Terminal based YouTube player and downloader