These extensions bring back the old features that has been removed on new Firefox
Status bar widgets and progress indicators for Firefox 4+
Restore squared tabs, appmenu, add-ons bar, small button view and more on Australis UI (Windows/MacOSX/Linux + Fx 29+).
v1.1.8 and 1.1.9 beta builds on versions page!
This restartless extension provides a separate downloads window.
Gives you a place to put all your add-on buttons without over-crowding the navigation bar.
Brings back the keyword.URL preference on Firefox 23 and up.
Add RSS icon back into location bar (URL) in Firefox 4.0. This icon was showed in Firefox 3.5/3.6 by default when page offered feeds.
Causes Firefox 3's Location Bar "AwesomeBar" to look and act more like Firefox 2's old location bar.
Has an options menu to set things just to your liking.
Returns the 'Properties' menu item that was removed in Firefox 3.6 to the context menu.
Since Firefox 25, the FindBar was made independent for each tab. This addon reverts the FindBar to classic/global behavior.
This extension makes "Bookmark This Page", "Bookmark This Tab" and "Bookmark All Tabs.." behavior equal with Firefox2.
Add "Undo" and "Redo" menu in context menu of bookmarks.
Restore Linkinfo and FormInfo which has been deleted from PageInfo of Firefox3.
This extension does not seem to work on MAC.