Simple Tab Groups - Create, modify and quick change tab groups. Features:
Workona - A better way to work in the browser.
Simplified Tab Groups - This Firefox addon provides tab grouping features similar to the removed TabView/TabGroups/Panorama...
OneTab - Whenever you find yourself with too many tabs, click the OneTab icon to convert all of your tabs into a list. When you need to access the tabs again, you can either restore them individually or all at once.
Panorama View - Tab Groups with Panorama View. Lets you easily Group and manage Tabs visually, with tab hiding.
Session Buddy - Manage Your Browser Sessions