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.
Image Hunter - Image Hunter – Search By Image is a tool that allows you to upload an image or images directly from your mobile device and find all the other existing sources of the image on Google.
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
JS Image Finder - JS Image Finder: Image Search is a powerful, simple, and easy to use application that allows you to search for images from the internet using popular search engines.
APKMirror - Android Market and APK Downloads
Camera Roll - Simple Gallery App for Android, with lovely Material Design.