Theme Font & Size Changer lets you change the global font size and font family used for the user interface in Firefox. Design your browser with your favorite font.
The One; The Original Fasterfox Gives performance & network tweaks for Firefox. Fasterfox makes your browsing so much faster!
Make your Sites Faster than a Fox with Fasterfox for FireFox!
Draw a ruler across any webpage to check the width, height, or alignment of page elements in pixels.
Image Block adds a toggle button that conditionally blocks/allows loading of images on webpages. Blocking images results in faster browsing, especially helpful on handheld devices or slower connections like GSM/GPRS/EDGE dial-up etc.
Install the MEGA Firefox extension for vastly improved download performance. It will allow you to batch-download an unlimited number of files without any size restrictions from MEGA.
Translate the whole entire page or just a selection using Google Translate.
Allows the download manager to also open in a tab or sidebar, and adds some optional display changes.
Notifier for gmail, yahoo, hotmail, aol and more webmails.
X-notifier(aka WebMail Notifier) checks your webmail accounts and notifies the number of unread emails...
Supports : gmail, yahoo, hotmail, POP3/IMAP, facebook, twitter and more
YSlow analyzes web pages and suggests ways to improve their performance based on a set of rules for high performance web pages.
http://yslow.org is the official open source website.
Paint your firefox white. Make it look simpler, nicer.
Notice: For Beta users, please download the latest development version.