Xamarin.Android - Integrated environment for building not only native Android but iOS and Windows apps too.
Jasonette - Make an app by adding JSON to this app.
RAD Studio - RAD Studio 10.2 with Delphi Linux compiler is the fastest way to write, compile, package and deploy cross-platform native software applications. Learn more.
AppyBuilder - An App Inventor 2 spin-off. Formerly called AILiveComplete.
Rider - Rider is a cross-platform .NET IDE based on the IntelliJ platform and ReSharper.
AppMySite - An automated no-code app builder