The decision reached on March 27, 2018 was that:
Google’s use of the Java API packages was not fair as a matter of law. 

PM> Install-Package MaterialShowcaseView

> dotnet add package MaterialShowcaseView

This is an alphabetical list of libraries for Android development, the majority being actively maintained. 

Along with NativeScript 3.4 we also released a new version of the nativescript-angular plugin with official support for Angular 5. The update includes support for Angular’s new AnimationBuilder APIs, as well as some iOS-specific startup time improvements. You can learn more about these changes in the nativescript-angular changelog. 

One of the most exciting announcements during this year’s Connect(); event was the ability to embed .NET libraries into existing iOS (Objective-C/Swift) and Android (Java) applications with .NET Embedding. This is great because you can start to share code between your iOS and Android applications, and you can also share the user interface between your apps when you combine .NET Embedding with Xamarin.Forms Native Forms. This means that you can leverage your existing investments and apps without having to re-write them from scratch to start adding cross-platform logic and UI. In fact, during the Connect(); keynote I showed how I was able to extend the open source Swift-based Kickstarter iOS application with .NET Embedding and Xamarin.Forms Native Forms. You can check out the clip below. 

ReactXP is a new Library by Microsoft for building cross platform apps that run on iOS, Android, Windows, and the web.