
Tab Utilities
Open Bookmarks/History/Homepage/URL/Search in new tabs, and more utilities for tabbed browsing, including open tab next, focus related/last visited tab, protect/lock/faviconize/pin tab, multiple tab handler, tab clicking options, etc.
Detects and automatically closes duplicate tabs.
Duplicate Tabs Closer detects and closes duplicate tabs.
Firefox extension Tabbed browsing
firefox-extension tabbed-browsing tabs-management tabs