Top 20 NuGet testing Packages

Unit test helpers for asserting public properties on class instances "mapped" from one type to another (via AutoMapper, another tool, or hand-written code) have the correct values.
Report Portal SpecFlow agent
Bumblebee is a .NET layer on top of the Selenium browser automation framework allowing for standardized creation of page objects, even for dynamic web pages.
QUnit installation into Bridge.NET projects.
Extends Selenium objects. Automation Wrapper Product which allows advanced and complicated Selenium actions with minimum code. Allows bi-directional interaction with Selenium. This package will not affect any current Selenium implementations it will only add extension methods to Selenium objects.
Data Contracts (DTOs) for all Gravity API Products
You will be able to manipulate Win32 Controls. This library is built on Friendly Layer.
ReportGenerator converts XML reports generated by OpenCover, dotCover, Visual Studio, NCover, or Cobertura or into human readable reports in various formats. The reports do not only show the coverage quota, but also include the source code and visualize which line has been covered. Use this package...
Machine.Specifications is a Context/Specification framework geared towards removing language noise and simplifying tests.
NCrunch.Framework is a run-time library for NCrunch users. This library contains attributes and tools that enable some very powerful features within NCrunch.
This extension allows NUnit to recognize and load NUnit projects, file type .nunit.
This extension allows NUnit to load and run tests compiled against earlier versions of the NUnit framework. Versions 2.0 through 2.6.4 are supported.
This extension allows NUnit to create result files in the V2 format, which is used by many CI servers.
This extension allows NUnit to recognize and load solutions and projects in Visual Studio format. It supports files of type .sln, .csproj, .vbproj, .vjsproj, .vcproj and .fsproj.
This extension sends specially formatted messages about test progress to TeamCity as each test executes, allowing TeamCity to monitor progress.
Advanced testing library for F#
Test harness for Nancy applications.
An open source code coverage tool (branch and sequence point) for all .NET Frameworks 2 and above (including Silverlight). Also capable of handling 32 and 64 bit processes. Use ReportGenerator 1.9 for best viewing results (also available via Nuget).
An implementation of IWebDriver in a mock class which does not open a browser and returns predefined elements and data. Used for unit testing selenium based frameworks
A C# class library that handles mocking, test data generation, and validation.