GifRun - GifRun provides easiest way to find and create animated GIFs from YouTube, Video, Images or Vine...
Enhancer for YouTube - Tons of features to improve your user experience on YouTube™!
CONV. - Convert YouTube video to MP3, GIF or MP4
Iridium by ParticleCore - Iridium is an extension built to improve the user experience on the new YouTube Material layout.
Turn Off the Lights - With a single click on the lamp button, the page will fade to dark.
Magic Actions for YouTube - Magic Actions is an extension that changes the way you’ll watch videos on YouTube.