DroidBull is described as 'Droidbull is the web app to provide premium mods of android apps and provide you best app of all categories'. There are more than 50 alternatives to DroidBull, not only websites but also apps for a variety of platforms, including Android, Android Tablet, Windows and Android Wear. The best alternative is F-Droid, which is both free and Open Source. Other great sites and apps similar to DroidBull are Google Play Store (Free), Aurora Store (Free, Open Source), Aptoide (Free, Open Source) and APKPure (Free).
Aurora Store is an unofficial, FOSS client to Google's Play Store with an elegant design. Not only does Aurora Store download, update, and search for apps like the Play Store, it also empowers the user with new features.
Aptoide is a distributed marketplace for mobile applications which runs on the Android operating system. In Aptoide, unlike the default Google Play Store, there is not a unique and centralized store but each user manages their own store.
The project's aim is to promote free and open source software on the Android platform. Fossdroid takes its data from F-Droid, but organizes apps in an attractive, Google Play-like arrangement with the ability to view apps by popularity.
In an effort to make things easy, and maybe even fun, AndroidPolice.com created APK Mirror. Over the past several months, they've been working to build a smooth, reliable, trust-worthy site to host the downloads users love. You also can upload APKs to the site yourself.
Software lets you install and update applications and system extensions. A plugin system is used to access software from different sources. Plugins are provided for: Traditional package installation via PackageKit (e.g. Debian package, RPM).