Below are list of some of the popular and well known Unit testing frameworks or libraries for .NET Developers.
Popular .NET Unit Testing Frameworks
This is a unit testing framework that was initially ported from JUnit and is written entirely written in C# .
Know more about NUnit at http://www.nunit.org/
Typemock Isolator .NET
This tool is from the company called Typemock . It lets you to test “untestable” code such as statics, privates and non-virtual methods.
Know more about Typemock Isolator .NET at http://www.typemock.com/isolator-product-page
The Gallio Automation Platform is an open, extensible, and neutral system for .NET that provides a common object model, runtime services and tools (such as test runners) that may be leveraged by any number of test frameworks.
Know more about mb-unit at http://code.google.com/p/mb-unit/
xUnit.net is a free, open source, community-focused unit testing tool for the .NET Framework.
Know more about xunit at https://github.com/xunit/xunit
TestDriven.Net makes it easy to run unit tests with a single click, anywhere in your Visual Studio solutions.
Know more about TestDriven.Net at http://testdriven.net/
Are there any other interesting testing frameworks or libraries that you have worked on ? . Feel free to share them in the comments section.