xUnit.net is a free, open source, community-focused unit testing tool for the .NET Framework.
Fluent API for asserting the results of unit tests that targets .NET Framework 4.5, 4.7, .NET Standard 1.3, 1.6 and 2.0. Supports the unit test frameworks MSTest, MSTest2, Gallio, NUnit, XUnit, MBunit, MSpec, and NSpec.
NUnit 3 Framework
Should testing for .NET - the way Asserting *Should* be!
Modern Testing for .NET
Easy integration testing helper for ASP.Net Core applications
List of Automated Testing (TDD/BDD/ATDD/SBE) Tools and Frameworks for .NET
.NET version of Pact. Enables consumer driven contract testing, providing a mock service and DSL for the consumer project, and interaction playback and verification for the service provider project.