1- Request Policy

RequestPolicy is an extension for Mozilla browsers that improves the privacy and security of your browsing by giving you control over when cross-site requests are allowed by webpages you visit. It is the first comprehensive client-side protection against CSRF attacks and the first tool to enable the use of modern browsers without cross-site information leakage.

It is compatible with Firefox 3+, SeaMonkey 2.0, Flock 2.0, Songbird 1.0, and Fennec 1.0. It works wherever these browsers do (Linux, BSD, Mac, Windows, etc.).
2- Quick Proxy

Quickproxy creates a statusbar button to turn the proxy on and off with a single click. This switches Firefox between the different proxy states that you have selected, which are configured through the Firefox preferences, and the type of proxy that is turned on/off is configured through the QuickProxy preferences window. This extension will not provide a proxy server for you.

3- Secure Login

Secure Login is a login extension for Mozilla Firefox integrated password manager.  Its main feature is similar to Opera’s (the browser) Wand login. Features Include:

• Works out of the box without any configuration needed.
• Login with one click or a keyboard shortcut (automatically submitting the login forms).
• Easy and convenient selection for multiple logins (multiple users)
• Provides direct login to any site from the bookmarks (using the “Secure Login Bookmarks”).
• Integrates with Mozilla Firefox password manager.
• Provides easy access to the saved passwords.
• Prevents malicious JavaScript code to automatically steal your login data.
• Provides an option to protect your login data from all JavaScript code during login.
• Websites requiring JavaScript for the login process can be added to an exception list.
• Can prevent cross-site scripting (XSS) attacks to steal your passwords without having to deactivate JavaScript.
• Helps to protect you from phishing.
• Shows the login URL(s) and the number of available logins in a tooltip of the toolbar button and the statusbar icon.
• Can be set to automatically search for login data and highlight form fields.
• Can be used with a toolbar button, a statusbar icon, a keyboard shortcut or via the context menu.
• Completely customizable interface (buttons, icons and menus can be enabled/disabled).
• Provides a customizable keyboard shortcut
• By default only active on login so it doesn’t consume any system resources while surfing.
• Can fill out additional form fields using the Autofill Forms add-on.
• Possibility to play a sound when logins are found or when logging in.

4- Better Privacy

Better Privacy serves to protect against not deletable longterm cookies, a new generation of ‘Super-Cookie’, which silently conquered the internet. This new cookie generation offers unlimited user tracking to industry and market research. Concerning privacy Flash- and DOM Storage objects are most critical.  This addon was made to make users aware of those hidden, never expiring objects and to offer an easy way to get rid of them – since browsers are unable to do that for you.

5- Tor Button

Torbutton provides a button to securely and easily enable or disable the browser’s use of Tor. It is currently the only addon that will safely manage your Tor browsing to prevent IP address leakage, cookie leakage, and general privacy attacks.

6- Lazarus: Form Recovery

Never lose anything you type into a web form again! Lazarus securely auto-saves all forms as you type, so after a crash, server timeout, or whatever, you can go back to the form, right click, “recover form”, and breath a sigh of relief.

7- Malware Search

Mainly for use with HijackThis logs, this plugin will search various malware related databases for selected (highlighted) text. Usage: Highlight some text (filename, dll, etc), right click and select “Malware Search” from the popup menu, find the database you wish to search, and then left click on that menu entry. A new tab will appear with the results. You can use the options menu to select which databases appear on the menu.

8- Remove Cookie(s) for Site

A very simple extension to remove all the cookies of currently opened site. It adds an option to the Right Click menu of the page, and a toolbar button to perform this operation. It displays the status of operation in the status bar.

iMacros was designed to automate the most repetitious tasks on the web. If there’s an activity you have to do repeatedly, just record it in iMacros. The next time you need to do it, the entire macro will run at the click of a button! With iMacros, you can quickly and easily fill out web forms, remember passwords, create a webmail notifier, download information from other sites, scrape the Web (get data from multiple sites), and more.

You can keep the macros on your computer for your own use, or share them with others by embedding them on your homepage, blog, company Intranet or any social bookmarking service. The uses are limited only by your imagination!

10-  FoxyProxy

FoxyProxy is a Firefox extension which automatically switches an internet connection across one or more proxy servers based on URL patterns. Put simply, FoxyProxy automates the manual process of editing Firefox’s Connection Settings dialog. Proxy server switching occurs based on the loading URL and the switching rules you define.

Animated icons show you when a proxy is in use. Advanced logging shows you which proxies were used and when. QuickAdd makes it a snap to create new URL patterns on-the-fly. FoxyProxy is fully compatible with Portable Firefox, has better support for PAC files than Firefox itself, and is translated into more than 25 languages.

11- McAfee SiteAdvisor

McAfee SiteAdvisor helps protect you from all kinds of Web-based security threats including spyware, adware, spam, viruses, browser exploits, phishing, online fraud and identity theft. Our automated testers continually patrol the Web to browse sites, download files, and sign-up for things with e-mail addresses. As you search, browse, download or register online, SiteAdvisor’s safety ratings help you stay safe and in control.

12- AdBlock Plus

Ever been annoyed by all those ads and banners on the internet that often take longer to download than everything else on the page? Install Adblock Plus now and get rid of them. Right-click on a banner and choose “Adblock” from the context menu — the banner won’t be downloaded again. Maybe even replace parts of the banner address with star symbols to block similar banners as well. Or choose a filter subscription, then even this simple task will usually be unnecessary: the filter subscription will block most advertisements fully automatically.

Users Choice:

Actually, I was going to put NoScript in but then I thought stating the obvious might not be a nifty idea :) – my apologies. For people who don’t know or have used this plugin, it’s a must recommended download.

NoScript

Winner of the “2006 PC World World Class Award”, this tool provides extra protection to your Firefox.

It allows JavaScript, Java and other executable content to run only from trusted domains of your choice, e.g. your home-banking web site, guarding your “trust boundaries” against cross-site scripting attacks (XSS) and Clickjacking attempts, thanks to its unique ClearClick technology.

Such a preemptive approach prevents exploitation of security vulnerabilities (known and even unknown!) with no loss of functionality…

Experts do agree: Firefox is really safer with NoScript ;-)