Privacy Badger

A tracker blocker rather than an ad blocker, and that is the point. Made by the Electronic Frontier Foundation, it watches for third parties following you from site to site and learns to block them, topped up by periodic learning updates so it does not start from zero. Ads that do not track you are left alone, which keeps it friendly to sites that rely on ordinary advertising. It also swaps embedded social buttons and similar widgets for click-to-activate placeholders, so nothing reports back until you choose to load it. It pairs well with uBlock Origin Lite on Chrome, and a site that misbehaves can have it switched off for that site alone. Available for Chrome, Firefox, Edge, Opera, Brave and Safari.