Enhancer for YouTube - Tons of features to improve your user experience on YouTube™!
GIFit! - Quickly turn YouTube videos into GIFs (chrome extension)
Iridium by ParticleCore - Iridium is an extension built to improve the user experience on the new YouTube Material layout.
Book Video Club - Quick video summaries of the top business books for startups
Magic Actions for YouTube - Magic Actions is an extension that changes the way you’ll watch videos on YouTube.
Wibbitz - Watch video summaries of the news you want.