Top 20 NuGet testing Packages

Selenium/MbUnit Test Automation Framework
You will be able to get the desired window. This library is built on Friendly Layer.
This is used for test automation of Windows applications. You can call the API of separate process from outside.
Machine.Specifications.Mvc is a set of extensions for testing ASP.Net MVC specific types. It aims to ease the testing of ActionResult objects returned from MVC Controllers by providing an Machine.Specifications (MSpec) BDD syntax over these types.
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.
Appender for System.Diagnostics to report log messages into ReportPortal
Simple, terse, fluent unit testing of ASP.NET MVC Controllers. ASP.NET MVC 4 version; install FluentMVCTesting if you are using MVC5 or FluentMVCTesting.Mvc3 if you are using MVC3.
A TestDriven.Net runner for the Context/Specification framework Machine.Specifications
White is a framework for automating rich client applications based on Win32, WinForms, WPF, Silverlight and SWT (Java) platforms. It is .NET based and does not require the use of any proprietary scripting languages. Tests/automation programs using White can be written with whatever .NET language, ID...
Library for robust UI test
My Tested ASP.NET Core MVC core components.
My Tested ASP.NET Core MVC view features components.
Canopy testing framework for mobile apps
Gravity API core functionality, which can be hosted as a service on platforms like Console Application, ASP.NET Web API, Service Fabric Service, .NET Core application, WCF Selfhost, etc. FREE register at "http://gravityapi.azurewebsites.net/Account/Register" in order to be able to use Gravity API
Mock implementation of IWebDriver which does not open a browser, for high performance testing of Selenium based frameworks, without a dependency on browsers and web drivers.
Akka testing helpers that help you test the relationships between your actors
Unofficial Report Portal SpecFlow agent
NMatcher is a simple library that eases tests (mostly with json).
Specification based testing with xunit
WPF extensions for ApprovalTests.