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.
Amazon Appstore - The Amazon Appstore is a place to purchase and download apps for your Android device.
APKStone - All apps in one place. Download APK files or from Google Play Store.
GetJar - Discover and play paid apps and games for free.
Aptoide - Aptoide is a third party replacement for the traditional Google Play Store.
AndroidPIT - Android news, apps, reviews, tips, hardware comparisons and forum