NoScript - NoScript for Firefox pre-emptively blocks malicious scripts and allows JavaScript, Java and other potentially dangerous content only from sites you trust. Download it now for free! - what is it?

uBlock Origin - Popular and efficient blocker for Chromium, Chrome, Edge, Firefox, Opera, Safari, Thunderbird.

uMatrix - uMatrix: A point-and-click matrix-based firewall, with many privacy-enhancing tools.

Ghostery - Privacy tool for transparency and control

RequestPolicy - RequestPolicy is an extension for Mozilla browsers that improves the privacy and security of your...

nuTensor - An fork of uMatrix. It features the same point & click system that forbids/allows any class of requests made by your browser. Same as uMatrix use it to block scripts, iframes, ads, facebook, etc. Currently in early development, only Firefox for now.