Top 20 NuGet utilities Packages

A robust library of .NET utilities
A Handy package for data handling.
Specification extensions and automocking utilities for interaction tests.
A reusable Google Calendar synchronisation implementation for .NET applications
The Cuemon namespace contains fundamental types such as value and reference types, factories and utility classes, interfaces, attributes and feature rich delegates that support functional programming on a whole new level. The namespace is an addition to the System namespace.
biz.dfch.CS.Testing ======================== Collection of utility classes that provide functionality for testing
Kode-Aid shared configuration library.
Kode-Aid shared AutoMapper library.
Common utilities for .NET applications
Common markdown classes for .NET applications
Agrona provides a library of data structures and utility methods that are a common need when building high-performance applications in .NET
West Wind Web MVC Utilities provides a number of small MVC helpers and utilities for dealing with controllers, viewmodels and error display and many utility functions.
Standard Web Applications .NET Utilities
Allows easy access to instance based performance counters and timers.
Cryptography utilities
Boilerplate code that can speed up your development
This tool allows to encrypt configuration sections on app.settings files, and decrypt the information in runtime adding those configuration as a singleton inside the application.
Easy repositories for .Net built on Dapper.
Help methods, data annotations, extensions, enumerations and options classes.
Indice.EntityFrameworkCore Class Library