uBlock Origin

uBlock Origin is a cross-platform, free and open-source browser plugin for content filtering, including ad blocking. The extension is available for the following browsers: Chrome, Chromium, Edge, Firefox, Opera, Pale Moon, and Safari versions prior to 13. uBlock Origin has gotten positive feedback from technology websites and is said to be far less memory-intensive than other extensions with comparable features. The stated goal of uBlock Origin is to provide users with the ability to impose their own (content-filtering) preferences.

Ublock Origin is a browser-based ad blocker that prioritizes simple, efficient blocking with little resource cost. The extension includes a number of filter lists for known advertising and malware sources, as well as the ability to read and build your own custom filters from hosts files.

Detailed information:
Cost: Free
Used by: 10M users
Link: https://addons.mozilla.org/en-US/firefox/addon/ublock-origin/