Free Firefox WebExtensions

uBlock Origin is a free and open-source browser extension for content filtering, including ad blocking. The extension is available for Firefox and Chromium-based browsers.

content filtering and ad blocking browser extension

Greasemonkey is a userscript manager made available as a Mozilla Firefox extension. It enables users to install scripts that make on-the-fly changes to web page content after or before the page is loaded in the browser (also known as augmented browsing).

AdBlock is an ad-blocking browser extension for Google Chrome, Apple Safari (desktop and mobile), Firefox, Samsung Internet, Microsoft Edge and Opera. AdBlock allows users to prevent page elements, such as advertisements, from being displayed. It is free to download and use, and it includes optional donations to the developers. The AdBlock extension was created on December 8, 2009, which is the day that supports for extensions was added to Google Chrome. It was one of the first Google Chrome extensions that was made.

NoScript (or NoScript Security Suite) is a free and open-source extension for Firefox- and Chromium-based web browsers, written and maintained by Giorgio Maone, a software developer and member of the Mozilla Security Group.

DownThemAll! (DTA) is a free and open source download manager browser extension. DTA can download all or some linked files, images, or embedded objects associated with a web page. It can pause, resume, or restart downloads.

AdGuard is a Cypriot company primarily offering ad blocking services. They offer dedicated ad blocking applications, browser extensions, a DNS resolver, and a VPN service.

open source privacy-enhancing web browser extension

open-source virtual private network service by Mozilla

Finnish company

browser add-on to block nonfree nontrivial JavaScript

Ghostery is a free and open-source privacy and security-related browser extension and mobile browser application. Since February 2017, it has been owned by the German company Cliqz International GmbH (formerly owned by Evidon, Inc., which was previously called Ghostery, Inc. and the Better Advertising Project). The code was originally developed by David Cancel and associates.

Wikimedia list article

style manager that can change the appearance of web pages in a user's browser

community project to analyze and grade the terms of service (TOS) and privacy policies of Internet sites and services

browser bookmarklet

Decentraleyes is a free and open-source browser extension used for local content delivery network (CDN) emulation. Its primary task is to block connections to major CDNs such as Cloudflare and Google (for privacy and anti-tracking purposes) and serve popular web libraries (such as JQuery and AngularJS) locally on the user's machine. Decentraleyes is available for Microsoft Edge, Mozilla Firefox + Firefox ESR, Google Chrome, Pale Moon and Opera web browsers.