Develop Desktop, Embedded, Mobile and WebAssembly apps with C# and XAML. The most popular .NET UI client technology

Dapper - a simple object mapper for .Net

Google's Material Design in XAML & WPF, for C# & VB.Net.

Mono open source ECMA CLI, C# and .NET implementation.

Simple REST and HTTP API Client for .NET

The most popular and friendly mocking framework for .NET

Stack Exchange's Monitoring System

Easy to use F#-like ~discriminated~ unions for C# with exhaustive compile time matching

Cross platform GUI framework for desktop and mobile applications in .NET

An easy service hosting framework for building Windows services using .NET

Git + .NET = ❤

A GitHub API client library for .NET

A small, happy, dynamic MicroORM for .NET that will love you forever.

MarkPad - a visual Markdown editor (inspired by the Downmarker project)

A cross-platform UI toolkit for creating desktop applications with .NET and Mono

Tool that uses Roslyn to automatically rewrite the source to follow our coding styles

The official repository for MonoTorrent, a bittorrent library for .NET

The code that powers Voat

Source browser website generator that powers https://source.dot.net, https://referencesource.microsoft.com and https://sourceroslyn.io

RoundhousE is a Database Migration Utility for .NET using sql files and versioning based on source control

Script# Project - a C# to JavaScript compiler, to power your HTML5 and Node.js web development.

A Git implementation for .Net and Mono

A collection of third party bindings for MonoTouch

Shape-shifting your forms experience in ASP.NET Core MVC

VncSharp is a GPL implementation of the VNC Remote Framebuffer (RFB) Protocol for the .NET Framework

NMemory is a lightweight non-persistent in-memory relational database engine that is purely written in C# and can be hosted by .NET applications.

sones GraphDB - opensource graph database

SisoDb - Simple Structure Oriented Db

Vixen 3