Auto Tab Discard - Auto Tab Discard a lightweight extension that uses the native method (tabs.
Firemin - Firemin will force Firefox to use less memory. It is safe to use, spyware free and completely free.
FooTab - This Chrome/Iron extension is inspired by the excellent Firefox extension - BarTab, although...
Dormancy - Dormancy 'retires' tabs that have gone unused for a while, freeing up that memory.
SpeedyFox - Boost Firefox, Skype, Chrome, Thunderbird in a Single Click!
BrightExplorer - Add a tabbed interface to Windows Explorer.