Top 20 NuGet check Packages

Classes to support a business logic layer or an API. Keep child-parent relationships in sync. Wrap a result with data along with a Successful flag and a list of messages. Keep business logic units separate, implementing ISideEffect. Check whether a list is dirty.
Provides a set of validation and runtime checking extension methods which permits a more fluent programming style.
Provides classes for reading, manipulating, authoring, and writing X9.100-187 Image Cash Letter files. Some special-purpose classes and methods are provided specifically to accelerate production of these files for JPMorgan Chase, but all of the following record types are supported for general-purpos...
Monads are logic in-between instructions and often called "programmable ; " a common monads (Maybe, Do, Return ....) that helps with null checks
OWIN Self-host / IIS (Helios) support for the Dotnet Microservice library
Peshkov.Web.Content.Check package description
Preconditions provide convenience static methods that help to check that a method or a constructor is invoked with proper parameter or not. In other words it checks the pre-conditions.
Simple property value checker
A very small tool to check the internet connectivity.very simple to use and easy to impliment in your project.
This package checks if there is an update available To start upload a text file like the following content on any web server: "1.0.0.0" Now if you want to change your newest version number just change your text file. If you want to change your current version number just change your assembly ...
Control Library to check Internet Connection, Wifi and Ehernet...
Pineapple is a set of core libraries that includes utilities, primitives, helper classes for .NET! The inspiration for Pineapple comes from Google's Guava framework.
Either drag the RapidSpellDialog and RapidSpellAsYouType spelling controls into your form, or programmatically create in C# or VB.NET (and it really is just a few lines of code).
CheckComboBox for WinForms
Checkbox Radiobutton Xamarin
Add empty string checks.
Nancy integration for NotDeadYet.
ASP.NET Core support for the Dotnet Microservice library
Argument Assertions provides a fluent, simple and easy to use API for checking valid argument values with strong compile time type checks.
Library to make generic object checks, it's primarily used to make a check if someone else has saved the item you're about to save while you had the object open.