Tabby is a Window & Tab Manager for Firefox that helps you organize & manage a lot of tabs at ease!
It can help you open, close, pin, and do many other things on tabs and windows quickly.
You can also drag around tabs to move it, open last used tab/window by using some simple keyboard shortcuts, and much more!
You can download it here: http://www.whatsyouridea.com/my-software/
Try it out!
Also, if you have some sweet ideas on how to improve Tabby, or if you found a bug in Tabby, go here to tell me about it: