Select some text, right-click and choose"Search image" in the menu, a Google Image tab will open with your results.
TinEye is a reverse image search engine. The extension adds a context menu item so you can search for an image to find out where it came from, how it is being used, if modified versions of the image exist, or to find higher resolution versions.
Enlarge thumbnails, and show images/videos from links with a mouse hover.
Dark YouTube theme - apply Black Youtube & Facebook Skin. Dark YouTube theme protects eyes by changing Youtube & FB colors to black
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
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
Open With PDF Reader addon send PDF links directly to a PDF viewer like Adobe Acrobat Reader. Compatible with new Firefox Quantum 57
The extension will help to download music from the VC for free to your computer, as well as any video in HD quality.