The decentralized international activist/hactivist collective known as Anonymous originated in 2003 on the imageboard 4chan. Anonymous members (known as Anons) can be distinguished in public by the wearing of Guy Fawkes masks in the style portrayed in the graphic novel and film V for Vendetta. However, some of the collective prefer to instead cover their face without using the well-known mask as a disguise. Some anons also opt to mask their voices through voice changers or text-to-speech programs.
The Wikipedia article on Anonymous (group) discussed the following hactivist events by Anonymous when I checked in September 2020: