Viddly

The best one-click YouTube downloader serving you with options of either MP3 or MP4 downloads at rapid speeds. This freeware has a built-in search, supports Full HD, 4K and 8K videos at up to 60 fps. Convert videos or one-click playlists downloads.

Ambivid

The ambient light player for your favorite web browser ! Ambivid is a lightweight plugin that creates light effects around Youtube's HTML5 video player that correspond to the video content, resulting in a more immerse experience.