F-Droid is an installable catalogue of FOSS (Free and Open Source Software) applications for the Android platform. The client makes it easy to browse, install, and keep track of updates on your device.
I got late to the party, I still use the Google Play Store, but I find some neat apps with Fdroid from time to time, and I was like "hey this isn't that bad" I feel weird to have spend so much time looking for individual APK files ngl.