Petal Search by Huawei adds APKMirror to your sources and allows you to install XAPK files
APKMirror Installer (Official) for Android - APK Download
Android: Safe Websites to Download APK Files - Technipages
APKGrabber is a fork of APKUpdater, an open source APK updater for people who need a quick way to download and update APKs from the Play Store, APKMirror and APKPure (now updates
APKMirror Installer (Official) for Android - APK Download