Rated 5 out of 5 stars
You can get a feature very like this that is built into Firefox. You can see the tab thumbs and close buttons, there is also a tab search. YOU DO NOT NEED THIS ADDON TO DO THAT! All you have to do is go to about:config, click I'll be carefull, then in the filter put "alltabs" then the first one will be "browser.allTabs.previews" right click and hit toggle to change this to true. Then were you would usually see the list all tabs button will be a button with four squares, click this to see all tabs. Enjoy!
Note: I put five stars even tho I have not used it.