Open source releases from Microsoft
Windows Forms is a .NET Core UI framework for building Windows desktop applications.
ML.NET is an open source and cross-platform machine learning framework for .NET.
CoreFX is the foundational class libraries for .NET Core. It includes types for collections, file systems, console, JSON, XML, async and many others.
Infer.NET is a framework for running Bayesian inference in graphical models
CoreCLR is the runtime for .NET Core. It includes the garbage collector, JIT compiler, primitive data types and low-level classes.
The Roslyn .NET compiler provides C# and Visual Basic languages with rich code analysis APIs.