I thought I would post this link here for F-Droid for those that do not have it. As I mentioned in the title FOSS refers to Free and Open Source Software. The way this app or apk works, is that it is a Marketplace, similar to Google Play, with the exception that most of the apps that are located on F-Droid are no longer supported by Google or fall within the Conditions and terms set forth by Google. Since, it is a marketplace it is difficult to determine what the total amount of apps are that would be available. I used this source earlier this morning to locate, the app known as "AdAway" which is a Pop-up blocker that was removed from Google Play a few months ago. Anyhow, here is the link to the website that houses the link to the Open Source F-Droid app, if downloading directly to your device make sure that the "Unknown sources" check box is enabled on your device.