Tabs Outliner - Next Generation Session, Windows, Tabs Manager and a TooManyTabs Solution That Really Works.
Google Forms - Simple web forms from Google.
Tree Style Tab - Tree Style Tab is an all-in-one Firefox extension that provides ability in order to operate tabs as a tree.
poll.ly - your perfect partner to gather ideas and opinions in real time
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.
Stay-Open Menu - Facilitates opening multiple tabs from the Bookmarks Menu and various other bookmark/history...