In the beginning was AdBlock - an addon for Mozilla (not Firefox - that didn't exist). I used it on the Mozilla browser, which became SeaMonkey. That died and was taken forward on Firefox as AdBlock Plus (because Adblock still existed) by Wladimir Palant. I used that too, for many years. Full story here. By the time Google Chrome came along Adblock no longer existed so somebody took (bought?) the name for a Chrome Extension.

Wladimir Palant still writes on security of browsers and mobile apps - for example this recent piece.

A few years ago I changed to ublock origin on Firefox. It was a lighter version - originally called μBlock (micro block) - developed by Raymond Hill.

Some ad-blockers containing the word 'AdBlock' or 'AdBlocker' are spyware. Both AdBlock Plus and uBlock Origin are OK.

Google has made changes to Chrome to prevent ad blockers working. They still work on Firefox.