uBlock Origin

Raymond Hill's uBlock Origin remained the most effective browser ad and tracker blocker with 45 million active users, blocking not just ads but malvertising (malicious ads that install malware), cryptomining scripts, and third-party trackers. Its "medium mode" blocking regime — requiring user education but blocking 99% of tracking — was consistently recommended by cybersecurity professionals as the single highest-ROI privacy improvement for non-technical users.