Mozilla is best known for its web browser, but the company also produces Firefox OS for a limited number of handsets. With a little sideways thinking, though, you can try some of its apps in Android.
Much like Google Chrome, Firefox supports webapps—the OS and apps are built with the same technology—and this is how you can bring Firefox OS to Android. Apps work like browser extensions, so they take up very little room making them ideal for older devices or those with limited storage. Download a copy of Firefox for Android from the Google Play Store, or update your existing copy to 29 or above.