Aptoide - Aptoide is a third party replacement for the traditional Google Play Store.
F-Droid - F-Droid is an interesting alternative for Android users who want to try something different and not have to use the Goole Play store all the time.
APK Pure - Download apk for Android with APKPure APK downloader. NoAds, Faster apk downloads and apk file update speed. Best of all, it's free
1Mobile Market - 1Mobile Market is one of the newest apps and games places where the exclusive download of games and apps is accessible.
Amazon Appstore - The Amazon Appstore is a place to purchase and download apps for your Android device.
APKMirror - Android Market and APK Downloads