Thoughtfully architected, obscenely fast, thoroughly enjoyable web services for all
ASP.NET Boilerplate - Web Application Framework
A flexible web framework supports .Net Framework and .Net Core
Simplify.Web is a lightweight and fast server-side .NET web-framework based on MVC and OWIN for building HTTP based web-applications, RESTful APIs etc.
A small cross-platform UI library that brings the simplicity of native UI development to the web
Lightweight, low-ceremony, framework for building HTTP based services on .Net and Mono
A lightweight, object-oriented (Model-View-Handler) framework for modern web development in .NET.