Working .NET Standard 2.0 Xamarin.Forms solution with iOS, Android, and UWP projects. Start with this, rename it, and add your dependencies and current code files for a smooth upgrade to .NET Standard 2.0. You must be on the latest edition of Windows 10 (minimum) build 16299 to support .NET Standard 2.0 and to run this UWP application.
seankanderson/NetStandard2-Xamarin.Forms-Base-Project
Includes iOS, Android, and UWP projects converted to .NET Standard 2.0
C#