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.
Save contacts - Save contacts app provides features through which users can select the desired data to create the backup in a variety of different formats.
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
SIM Contacts Manager - SIM Contacts Manager app offers features that let you insert your sim card to your mobile phone to manage, edit, add, and delete your contacts right at your fingertips.
APKMirror - Android Market and APK Downloads
X-Transfer - X-Transfer is an app by WebToGo that comes up with features to help you in performing data transfer between your smart devices in a few simple steps.