GifRun - GifRun provides easiest way to find and create animated GIFs from YouTube, Video, Images or Vine...
Youtube Plus - Home of the extension YouTube Plus that allows you to experience more on YouTube - ParticleCore/Particle
CONV. - Convert YouTube video to MP3, GIF or MP4
Turn Off the Lights - With a single click on the lamp button, the page will fade to dark.
SmartVideo - SmartVideo is a tool that offers users better experience on YouTube as it enables users to have better control over YouTube buffering, and playing options.
SliceTube - The Fast and Modern way to cut and download YouTube videos