ImprovedTube - Allows you to improve and enhance Youtube visually or enable dozens of new features permanently or...
Yout - YouTube to Mp3 Converter
Enhancer for YouTube - Tons of features to improve your user experience on YouTube™!
Softorino YouTube Converter - Download YouTube video & audio. Watch and listen offline
Magic Actions for YouTube - Magic Actions is an extension that changes the way you’ll watch videos on YouTube.
You-Get - Command-line utility to download media contents from the web