Undo Close Tab Button VS Open Tabs Next to Current

Undo Closed Tabs Button - Add a toolbar button onto any toolbar to undo closed tabs

Tabs Outliner - Next Generation Session, Windows, Tabs Manager and a TooManyTabs Solution That Really Works.

Tab Utilities - Tab Utilities is an ultimate tab solution for all kind of users who want to manage their tab, create multiple session and search for new tabs, etc.

Undo Close Tab - Reopens the last closed tab.

Tree Style Tab - Tree Style Tab is an all-in-one Firefox extension that provides ability in order to operate tabs as a tree.

Duplicate Tabs Closer - Detects and automatically closes duplicate tabs.