With the TooManyTabs add-on you can now store up to over 50 tabs in multiple extra rows in the Firefox browser. 
Instead of allowing idle tabs to waste your PC’s memory, you can now put your tabs on the extra rows, remove them from the memory, and restore them in your browser when you need them again. The extra rows also allow you to better prioritize and visualize your tabs. Finding the right tab have never been easier !
Function OF TooManyTabs Addon
- Multiple rows for storing up to 50 tabs ,Restore up to 20 recently closed tabs ,Marking tabs in different colors ,Options to customize number of rows, Option to open tabs adjacent to your selected tab, Open all tabs of the same row in TooManyTabs
- Pin your most frequently visited tabs onto TooManyTabs and access them easily anytime,- Pinned tabs will stay on the TooManyTabs row unless you unpin them; clicking a pinned tab will open a new instance of the tab.
- Auto hide TMT row with adjustable delay, Adjust the minimum width of TMT tabs, New Options dialog accessible from TooManyTabs directly ,Clear Recently Closed Tabs History , Show and Hide TMT row by toggle button
You can Download this TooManyTabs Addon from Official website of Firefox Addon.