Caprine

Free FROM Sindre Sorhus, sindresorhus.com NEEDS OS X 10.10 or later

While Franz takes a wide–net approach, Caprine focuses exclusively on Facebook Messenger, but in doing so offers more features. It’s especially useful if you’re privacy–minded, letting you block read receipts, stifle link tracking, and obfuscate desktop notifications in the notoriously data–hungry app.