List of the Best Firefox Extension.

Url: https://addons.mozilla.org/en-US/firefox/addon/500

Description: Adsense Notifier displays your Adsense earnings on the Firefox statusbar and automates the login process to Google Adsense.

Url: https://addons.mozilla.org/en-US/firefox/addon/570

Description: SEOpen - Search Engine Optimization tools.

Url: https://addons.mozilla.org/en-US/firefox/addon/60

Description: Web Developer - Contains many Web Developer tools.

Url: https://addons.mozilla.org/en-US/firefox/addon/722

Description: NoScript - Block and allow java script to be executed.

https://addons.mozilla.org/en-US/firefox/addon/5648

Description: FireShot is a Firefox extension that creates screenshots of web pages and provide the editing and annotation tools, which let users quickly modify captures and insert text and graphical annotations.

other:

https://addons.mozilla.org/en-US/firefox/addon/220

https://addons.mozilla.org/en-US/firefox/addon/201

https://addons.mozilla.org/en-US/firefox/addon/636

https://addons.mozilla.org/en-US/firefox/addon/1146

https://addons.mozilla.org/en-US/firefox/addon/3036

https://addons.mozilla.org/en-US/firefox/addon/1249

LinkChecker - https://addons.mozilla.org/en-US/firefox/addon/532

NoReferrer - https://addons.mozilla.org/en-US/firefox/addon/1999