Add-ons which fix bugs, improve security, or add functionality that should be included in Firefox by default. See also my collections "privacy essentials", "functionality" and "newbie-suitable".
The best security you can get in a web browser!
Allow active content to run only from sites you trust, and protect yourself against XSS and Clickjacking attacks.
Collector's Note Although it makes browsing a little annoying, real security is impossible without it.
Never be annoyed by a Flash animation again! Blocks Flash so it won't get in your way, but if you want to see it, just click on...
Collector's Note Adobe Flash is one of the biggest security vulnerabilities in your browser: don't load Flash on random websites.
Session Manager saves and restores the state of all or some windows - either when you want it or automatically at startup and after crashes. It can also automatically save the state of open windows individually.
Use PDF Download to do whatever you like with PDF files on the Web. Regain control and eliminate browser problems, view PDFs directly in Firefox as HTML, and use the all-new Web-to-PDF toolbar to save and share Web pages as high-quality PDF files.
— Open web pages saved with Internet Explorer or other browsers (MHT)
— Save many tabs, video and audio reliably, in a single ZIP file (MAFF)
— Return to the original site you saved a page from, and more!
Collector's Note The far superior way to save webpages.
Status bar widgets and progress indicators for Firefox 4+
Encrypt the web! HTTPS Everywhere is a Firefox extension to protect your communications by enabling HTTPS encryption automatically on sites that are known to support it, even when you type URLs or follow links that omit the https: prefix.
Various enhancements for build-in "master password" (MP)
-Locks master security device on demand or after specified time
-Prompts for MP on browser startup
-Suppresses all or duplicate MP prompts
-Locks up entire application or individual windows
Collector's Note Re-prompts you for your master password after a set period of time. Can also lock your Firefox session after a period of time.
Do you know where your form information is going? This extension displays the form action (the site to which the information you've entered is being sent.) In any place where you can enter data, from search boxes to order forms, mouse over the...
British English Dictionary R1.19 for Firefox, Thunderbird and SeaMonkey by David Bartlett.
To enable, right-click in a multi-line text box, select "Languages", then "English / United Kingdom".
Add "Go Parent Folder" menu to context menu in The Library list view and Search result in Bookmarks Sidebar.
Save automatically the content in Textarea.
Collector's Note Don't lose what you're writing ever again.
Use identicons to automatically generate favicons for sites without one.