Top 20 NuGet Unit Testing Packages

Easily create fake HTTP endpoints for integration testing
Cross-platform performance benchmarking and testing framework for .NET applications.
Hedgehog with batteries included: Auto-generators, extra combinators, and more.
Easy-to-use test run reporter for MSTestV2
Simple package for internal logging into Seq server
MVC functional tests with a fixture pattern
Snapshark Adapter for Xunit
Easy way to tests queries generated by EntityFramework.
Provides infrastructure to build automated testing with Azure Event Grid.
Provides some additional xunit abstractions to make integration tests easier.
Sourcery for SauceLabs - Unlocking SauceLabs capability
Useful tools when unit testing applications that use Entity Framework Core. See readme file on github.
NUnit addin for reporting test results into ReportPortal
Machine.Specifications (MSpec) adapter for .NET Framework and .NET Core including dotnet cli (dotnet test), Visual Studio IDE, TFS, Visual Studio Online, Visual Studio Team Services.
TestKit for writing tests for Akka.NET using NUnit.
Tooling to empower BDD-style unit testing conventions; R# snippets for easier usage are available by project URL
A Photon plugin for invoking NUnit.
TestFountain is a set of addons/extensions for xUnit.net to help with things like data generation.
XUnit extensions in order to have new attributes. The attributes depending how you use them can be fully discoverable or more simple and not fully displayed in your test explorer. - Theory + FileData: Load the file content as string - Theory + JsonFileData: Load the JSON file into a typed object - ...
Specification based testing with xunit