GIFit! - Quickly turn YouTube videos into GIFs (chrome extension)
Enhancer for YouTube - Tons of features to improve your user experience on YouTube™!
Book Video Club - Quick video summaries of the top business books for startups
ImprovedTube - Allows you to improve and enhance Youtube visually or enable dozens of new features permanently or...
Youtube Plus - Home of the extension YouTube Plus that allows you to experience more on YouTube - ParticleCore/Particle
Iridium by ParticleCore - Iridium is an extension built to improve the user experience on the new YouTube Material layout.