The Customer Factor - Field Service Management
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.
Padlet - Visual boards for organizing anything.
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
Aurora - Download apks from Google Play Store
APKMirror - Android Market and APK Downloads