Umami is a simple, fast, open-source website analytics alternative to Google Analytics.
Matomo (formerly Piwik) is an open source Google Analytics alternative that gives you full control over your data and protects user privacy
Plausible is an open-source, lightweight web analytics tool. Your website data is 100% yours and the privacy of your visitors is respected.
Countly is an open source analytics platform to understand and enhance customer journeys in web, desktop and mobile applications.