Weaponizing Your Web Browser
An ordinary web-browser is already in many ways an extremely versatile security tool. However with the addition of just a few select plugins, you can also easily configure your browser to provide a application security assessment platform.
While there are a large number of Firefox plugins that have utility for security assessments, there is also a great deal of feature overlap between several of these projects. For a more comprehensive list of Firefox pentest plugins you can my plugin collection listed here:
DefendLink - Appsec Addons Collection
Here are 10 plugins that are extremely useful and provide unique functionality for application pen-testing (compatible with FF version 23.0 and above):