NSwag is a Swagger/OpenAPI 2.0 and 3.0 toolchain for .NET, .NET Core, Web API, ASP.NET Core, TypeScript (jQuery, AngularJS, Angular 2+, Aurelia, KnockoutJS and more) and other platforms, written in C# ...
Basic - simple 'Hello GraphQL!' example based on console version from GraphQL for .NET on GitHub, but using ASP.NET Core, Entity Framework Core and some best practices, patterns and principles.