Top 20 NuGet extension Packages

An extension that helps with building installers for .Net applications and websites with WiX. It's like Heat, but simpler and more focused for .Net development.
The extension framework to simplifies website development
A set of useful extension methods for the .NET language runtime.
Common reflection tasks implemented as extension methods.
A library that contains nice-to-have functionality that is missing in the .NET Framework.
BCL.Extension
A .NET library containing LINQ-to-Object extension methods for working with TPL Tasks. Feedback welcome.
A functional library for raising .NET events where a monadic structure is built around System.EventHandler<T>.
The project contains some of a very useful helpers and extension methods for .NET
Qi4CS Extension: Configuration is an extension of Qi4CS.Core that provides basic API for assembling composites that can be deserialized and serialized by ConfigurationManager, which is also provided by this extension. The configuration composites may have their location specified at assembling time ...
Qi4CS Extension: Configuration (XML) is an extension of Qi4CS.Core that further augments Qi4CS.Extensions.Configuration by adding customizable XML (de)serialization support for configuration composites.
This package to privide RadiobuttonList and CheckboxList for your asp.net mvc project
C# .net extension methods
Véritable couteau suisse du .net, rlcx Power tools contient une énorme quantité d'outils plus utiles les uns que les autres.
Query selector support for Selenium WebDriver.
Code eXtensions
Simit Extension Library
Extension methods for some System classes, packaged as source.
Extension methods for some System.Collections classes, packaged as source.
Extension methods for some System.IO classes, packaged as source.