TestDriven.NET
makes it easy to run unit tests with a single click, anywhere in your
Visual Studio solutions. It supports all versions of Microsoft Visual
Studio and it integrates with the best .NET development tools.
As the leading code coverage tool for Microsoft .NET software,
NCover
monitors your code while running under test and reports where your code
is being exercised (and more importantly, where it is not being exercised).
NDepend is a tool that simplifies managing complex .NET code base. Architects and developers can analyze code structure, specify design rules, plan large refactoring and master evolution.
MbUnit is the Generative Unit Test Framework for the .NET Framework. It provides advanced unit testing support with advanced fixtures to enable developers and testers to test all aspects of their software.
Rhino.Mock: A dynamic mock object framework for the .Net platform. It's purpose is to ease testing by allowing the developer to create mock implementations of custom objects and verify the interactions using unit testing.