Top 20 NuGet argument Packages

Terse syntax C# command line parser for .NET. For FSharp support see CommandLineParser.FSharp. The Command Line Parser Library offers to CLR applications a clean and concise API for manipulating command line arguments and related tasks.
A declarative command line and XML configuration parser for F# applications.
Model your command line application interface in a class
Argument validation made simple and unified. It ensures arguments conforms to simple validation rules and provides an uniformed exception throwing strategy if arguments are invalid.
Cauldron.Consoles is a Cauldron.Core based parameter parser which supports grouping of parameters in execution groups. It is also supports localization and has a nice parameter table :)
NClap is a .NET library for parsing command-line arguments and building interactive command shells. It's driven by a declarative attribute syntax, and easy to extend.
A simple guard library for validating method parameters without being a complete validation library. This library makes it easy to validate method arguments in a uniform way.
A simple library for reading command-line arguments.
Argument validation methods, for example: this.user = Argument.NotNull("user", user). Less fancy than approaches based on lambdas/anonymous classes, but less scary performance-wise (given that argument checks are often all over the place). Includes Code Contracts [ContractArgumentValidator] annota...
Ensure.Net is a null checker library for .NET
Command line arguments parser. See https://github.com/dimaaan/NOpt
Terse syntax C# command line parser for .NET with F# support. The Command Line Parser Library offers to CLR applications a clean and concise API for manipulating command line arguments and related tasks.
CuttingEdge.Conditions is a library that helps developers to write fluent pre and postcondition validations in their C# 3.0 and VB.NET 9.0 code base. Writing these validations is easy and it improves the readability and maintainability of code.
ConsoleCommon is a .net library that provides a set of helper tools intended for use with console applications. These tools focus on automating argument typing and validation, and creating help text.
Simple CommandRunner to bootstrap console applications
Model your command line application interface in a class
Model your command line application interface in a class
Command-line argument parser.
A .NET library for parsing command line options with subcommands (like git or svn).
Command line argument parser.