Auto Unload Tab Alternatives
Auto Unload Tab is described as 'If you one of those persons who like to have much open tabs in Firefox browser, then you know how many PC resources that consumes. The solution is simple - unload unused tabs after some period of inactivity (user sets the time)' and is an app in the web browsers category. There are more than 10 alternatives to Auto Unload Tab for a variety of platforms, including Windows, Firefox, Mac, Linux and Self-Hosted solutions. The best alternative is Tabs Outliner, which is free. Other great apps like Auto Unload Tab are Tab Mix Plus, Firemin, Duplicate Tabs Closer and Open Tabs Next to Current.
Next Generation Session, Windows, Tabs Manager and a TooManyTabs Solution That Really Works.
Features
Tab Mix Plus enhances Firefox's tab browsing capabilities. It includes such features as duplicating tabs, controlling tab focus, tab clicking options, undo closed tabs and windows, plus much more. It also includes a full-featured session manager with crash recovery that can...
Features
Firemin is a small utility to reduce the amount of memory Firefox or other browsers use. Although Firefox memory usage improved a little over the last few years, it still uses a lot of memory; a little more than we feel comfortable with.
Detects and automatically closes duplicate tabs.
Features
Always open new tabs to the right of the current one(which is not the same as setting browser.tabs.insertRelatedAfterCurrent to true). You can however get the default behaviour by:
Features
PHP script for generating multilevel tab menu control. Fast, flexible and easy customizable solution for navigation system of your website.
Open Bookmarks/History/Homepage/URL/Search in new tabs, and more utilities for tabbed browsing, including open tab next, focus related/last visited tab, protect/lock/faviconize/pin tab, multiple tab handler, tab clicking options, etc.
DiscontinuedThe extension is no longer developed since 2014 and doesn't work on Firefox 57. The extension still works on XUL-based Firefox forks like
Waterfox and 
Pale Moon
An essential add-on for power users that have many tabs open. Curb your resource usage by unloading tabs that you haven't visited for a while. An unloaded tab is restored back to its original state when you need it again.
Features
DiscontinuedThe last update was on February 11th, 2014.
Displays how many tabs are open. The count includes tabs from all windows. Also indicates how many tabs actually have content loaded in them – for example, after restarting Firefox.
Features
Dormancy 'retires' tabs that have gone unused for a while, freeing up that memory. It then restores the tabs to life when accessed.
Features
DiscontinuedThe last update was on June 17th, 2012.