Awesome
Sundown.net
Sundown.net provides .NET bindings for the nice and popular sundown markdown library.
The aim of this library is to provide all the functionality that sundown provides alongside the possibility to do stuff quickly (simple API).
It is ridicolously fast compared to pure .NET/Regex implementations.
More information on the official website.
License
The wrapper is available under the MIT license. Note that the actual library is not licensed under the MIT license.