YouTube High Definition is a powerful tool that will let you automatically play all YouTube videos in HD (High Definition), turn off annotations, change video player size, auto stop videos, auto mute videos, control embedded videos and much more.
Select some text, right-click and choose"Search image" in the menu, a Google Image tab will open with your results.
Enlarge thumbnails, and show images/videos from links with a mouse hover.
Easily download most popular video formats.
瞬间过滤B站(bilibili.com)刷屏的相似弹幕，还你清爽的弹幕视频体验。 *a tweak for a Chinese website. Please ignore this add-on if you are not a user of bilibili.com.*
Tons of features to improve your user experience on YouTube™.
Stops video autoplay and shows the preview thumbnail.
Reverse image search using various search engines, such as Google, Bing, Yandex, Baidu and TinEye.
Open and download links in IDM (Internet Download Manager) easily
Experience a beautiful image from Google Earth every time you open a new tab.
Open With PDF Reader addon send PDF links directly to a PDF viewer like Adobe Acrobat Reader. Compatible with new Firefox Quantum 57
The YouTube Mp3 Downloader Add-on includes a Button on any YouTube Page and allows you to convert the YouTube Video to a Mp3 with just one click. Compatible with new Firefox Quantum 57