Top 20 NuGet common Packages

Provides common simple helper functions to accelerate .NET development. Those vary by complexity and nature and include a lot of extension methods to calculate hashes (md5, crypto), string operations, short guids, string encoding, collection extensions, CSV support and many more.
ServiceStack Templates, Virtual File System, SimpleContainer and Common library for ServiceStack projects.
JSON, XML, JSV, SOAP and MQ Generic Service Clients.
Provides infrastructure for common error handling, tracing, configuration, and HTTP/REST-based pipeline manipulation for REST clients generated with Hyak.
Lykke common tools and utilities
.NET Standard 2.0 version of ServiceStack.Client
.NET Standard 2.0 version of ServiceStack.Common
common netfx and netstandard libarary,extensions helpers and useful utilities
Common calendar classes for .NET applications
A reusable Google Calendar synchronisation implementation for .NET applications
A set of useful methods used across Easy.* projects.
Common utilities for .NET applications
JSON ServiceClient implementation based on .NET's HttpClient
PostSharp.Patterns.Diagnostics: support for Common.Logging.
Dapplo.Windows.Common is a library which contains common files for Dapplo.Windows projects
Kode-Aid shared common library.
Assortment of various common types and utilities for Emzi0767's projects.
Gives some useful infrastructure classes.
A .NET Core Common Lib, Framework and Boilerplate.
Laobian.Common is shared library for private usage only