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
APKMirror - Android Market and APK Downloads
TorrApk - Alternative store for free Android apps
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.
Evozi APK Downloader - Download APKs directly from http://alternativeto.net/software/android-market/ to your computer.
Aptoide - Aptoide is a third party replacement for the traditional Google Play Store.