The top 25 most used Firefox add-on in Privacy & Security category

Finally, an efficient wide-spectrum content blocker. Easy on CPU and memory.

Automatically learns to block invisible trackers.

Simple and seamless privacy protection for your browser: tracker blocking, cookie protection, DuckDuckGo private search, email protection, HTTPS upgrading, and much more.

Unmatched adblock extension against advertising and pop-ups. Blocks ads on Facebook, Youtube and all other websites.

The best privacy tool and ad blocker extension for Firefox. Stop trackers, speed up websites and block ads everywhere including YouTube and Facebook.

At home, at work, or on the go, Bitwarden easily secures all your passwords, passkeys, and sensitive information.

Remove all annoying ads from YouTube.

Removes tracking elements from URLs

The best security you can get in a web browser! Allow potentially malicious web content to run only from sites you trust. Protect yourself against XSS other web security exploits.

Protects you against tracking through "free", centralized, content delivery. It prevents a lot of requests from reaching networks like Google Hosted Libraries, and serves local files to keep sites from breaking. Complements regular content blockers.

FoxyProxy is an open-source, advanced proxy management tool that completely replaces Firefox's limited proxying capabilities. No paid accounts are necessary; bring your own proxies or buy from any vendor. The original proxy tool, since 2006.

Control your cookies! This WebExtension is inspired by Self Destructing Cookies. When a tab closes, any cookies not being used are automatically deleted. Keep the ones you trust (forever/until restart) while deleting the rest. Containers Supported

Spoof websites trying to gather information about your web navigation—like your browser type and operating system—to deliver distinct content you may not want.

Make the web faster, more private, and more secure.

A customizable, password-protected website blocker and redirector.

Strictly block all popup requests from any website by default. A notification window is opened to allow you accept, reject, open the popup in background page, or redirect the current page to popup address

Removes the annoying link-conversion at Google Search / maps / ...

Save an entire web page—including images and styling—as a single HTML file.

RoboForm, the #1 ranked Password Manager makes your life easier by remembering passwords and logging you into websites automatically

Removes and prevents popups, overlays and cookie notifications, other tools do not. Enjoy the original look of the internet.

Alters some JS APIs to prevent fingerprinting.

Collection of Tab Related Actions e.g. Duplicate, Close Duplicates, Close to the Left, Copy Title, Merge Windows, Save as PDF, Copy Urls Tab/All/Left/Right, Host keep/close/close other, Sort by URL/Title, Asce/Desc, Move, Reload, Reload Timer

Delete browsing data directly from the browser toolbar. Clear cookies, history and cache with a single click.

Deletes browsing history older than a specified number of days.

One of the most popular free ad blockers for Firefox. Block annoying ads on sites like Facebook, YouTube and all other websites. Adblock Plus blocks all annoying ads, and supports websites by not blocking unobtrusive ads by default (configurable).