uBlock Origin - Popular and efficient blocker for Chromium, Chrome, Edge, Firefox, Opera, Safari, Thunderbird.
Spike - Spike solves businesses' communication chaos by bringing together email, team chat, collaborative docs, and meetings, into one feed.
Adblock Plus - AdBlock Plus is a browser extension for Firefox, Chrome, Opera, and several other popular browsers that prevents intrusive ads like pop-ups and malicious code from appearing on websites you visit.
Keybase Chat - End-to-end encrypted chat built into Keybase
AdGuard - Surf the Web Ad-Free and Safely. Shield up!
Crypho - End-to-end-encrypted messaging and file sharing