GoodBarber - GoodBarber is a mobile app creation platform.
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.
Dropsource - Mobile development platform for building native iOS & Android apps
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
Bizness Apps - Create your own app or become a reseller and build apps for others
APKMirror - Android Market and APK Downloads