Blocks annoying video ads on YouTube, Facebook ads, banners and much more.
Adblock Plus blocks all annoying ads, and supports websites by not blocking unobtrusive ads by default (configurable).
LastPass, an award-winning password manager, saves your passwords and gives you secure access from every computer and mobile device.
AutoPager automatically loads next pages when you reach the end of a page. It works on a ton of sites,Google,Yahoo..
It works well with most other add-ons adblock plus, WOT and most of the greasemonkey scripts.
You can also try AutoPagerLite.
AddThis for Firefox is the best add-on to make sharing and bookmarking simple. Have all your favorite web 2.0 social networking, bookmarking, blogging, and e-mail services at your fingertips. Share any page, anytime, with anyone.
As of Firefox 33, Venkman *no longer works*, as the APIs which it needs have been removed.
Shareaholic is the easiest way to share interesting links using Facebook, Twitter, Google Mail, Reader, Bookmarks, Evernote, Bitly, StumbleUpon, and more... from one simple ALL-IN-ONE add-on. This is the ultimate tool for the link sharing addict!
ShareThis for FireFox makes sharing simple. Share anything on the web with your friends on 45+ social sites including Facebook, Twitter, Email, Digg, Reddit and more. Track top trending shares by site and automatically save content to your ShareBox.
Collections are groups of related add-ons that anyone can create and share.Explore Collections