FEBE (Firefox Environment Backup Extension) allows you to quickly and easily backup your Firefox extensions. In fact, it goes beyond just backing up -- It will actually rebuild your extensions individually into installable .xpi files.
Customize application menus:
Rearrange or remove menuitems from the main context menu (right-click menu) and main menubar (File Edit View etc.)
Lets you load pages in IE with a single right-click, or mark certain sites to *always* load in IE.
Extends the function of the drag-and-drop mouse gesture so that it can be used to load URLs, do a web search of selected text on a page, or save an image on a page. The successor to Super DragAndGo.
CLEO (Compact Library Extension Organizer) is a Firefox extension that works with FEBE* to package any number of extensions/themes into a single, installable .xpi file.
Automatically save downloads to different directories when using "Save Link As..." or "Save Image as..."
Note from Mozilla: This add-on has been discontinued. Try DragIt instead.
Allows you to open links in new tabs, and do more with drag and drop gestures easier.
Creates a formatted page from bookmarks.
（alt. "BookmarksHome" for Firefox1.5）