Chrome: Pig Toolbox is a Chrome extension that features a bunch of different functions all rolled into one simple extension. It includes mouse gestures, a collection of YouTube related tools, an automatic Google Mail checker, and more.
As the name implies, Pig Toolbox is a collection of tools that all exist inside of one single extension so you don't have to have a bunch of different extensions filling up your toolbar. On top of the features mentioned above, Pig Toolbox also lets you configure a number of contextual shortcuts, take screenshots, create blocklists, and plenty more. A number of the functions are Windows-only, but if Pig Toolbox happens to have features you use regularly it's worth checking out. Find the full list of everything in the toolbox on the Chrome Web Store.
Pig Toolbox | Chrome Web Store via Techdows


Chrome/Firefox: Ever run into a video that's blocked because you aren't in a supported region? It's annoying, but ProxMate is a simple extension for Chrome and Firefox that unblocks region-specific content from YouTube, Hulu, and Grooveshark.
Yahoo! has released a new extension for Chrome, Internet Explorer, Firefox, and Safari that provides visual previews of search results instead of the typical plain text. They've also launched a new app for iPhone and iPad that wraps the search style into a browser.