GIFit! - Quickly turn YouTube videos into GIFs (chrome extension)
you-tldr - Get the tldr of any YouTube video in seconds
Turn Off the Lights - With a single click on the lamp button, the page will fade to dark.
tubecut. - The only YouTube downloader allows you to trim specific time
Youtube Plus - Home of the extension YouTube Plus that allows you to experience more on YouTube - ParticleCore/Particle
TLDR This - Automatically summarize any article or webpage in a click.