Aptoide - Aptoide is a third party replacement for the traditional Google Play Store.
Altstore - A home for apps that push the boundaries on iOS
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
Cydia - An alternative app store for jailbroken devices.
Amazon Appstore - The Amazon Appstore is a place to purchase and download apps for your Android device.
iOS Haven - A listing of tweaked apps and games for iOS devices. Install directly from the browser.