F-Stop Media Gallery - Image and video organizer.
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.
A Photo Manager - Manage local photos on Android: gallery, geotag with photomap, tags, find, sort, view, copy...
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
LeafPic - LeafPic is a fluid, material-designed alternative gallery.
APKMirror - Android Market and APK Downloads