CoreWCF 1.0 has been Released, WCF for .NET Core and .NET 5+ 

• Performance and stability improvements.
• Optimization and testing for .NET 6.
• All UIs and templates have been updated for “.NET 6” style, which means they now use the new hosting API, and all UIs have been converted to Razor pages.
• Added support for CIBA, which was the last missing piece for full FAPI compliance. 

Rider 2021.2: Support for ASP.NET Core Endpoints, Blazor WebAssembly Debugging, and More | The .NET Tools Blog 

Deno is a new runtime for executing JavaScript and TypeScript outside of the web browser. 

• New responsive containers! Over a year in the making, fluid up to a particular breakpoint, available for all responsive tiers.
• New responsive .row-cols classes for quickly specifying the number of columns across breakpoints. This one is huge for those of you who have asked for responsive card decks. 

A cross-platform library for the processing of image files; written in C# 

The NuGet 4.0 Package Manager Extension is currently not available for Visual Studio 2015 

• Non-nullable Types
  
• Control Flow Analysis for Types
  
• Easier Module Declarations  
  

• New: You can now create and install custom shapes for the Shapes tool.