Top 20 NuGet extensibility Packages

Clide
Lightning fast MEF engine, supporting System.ComponentModel.Composition and System.Composition.
Extensibility library.
Visual Studio Project System Extensibility
A simple library for loading plugins.
Build tools used for building extensions to the Visual Studio project system.
The MEF attributes and runtime classes in the .NET Managed Extensibility Framework (MEF) that are used for imports and exports, and exception types, in a .NET Standard compliant NuGet package form, as found in the System.ComponentModel.Composition namespace.
Diverse, the Fuzzer pico library you need to make your .NET tests more *Diverse*
An implementation of the Tcl scripting language.
An Autofac extension to Rhyous.SimplePluginLoader.
An implementation of the Tcl scripting language.
An implementation of the Tcl scripting language.
An implementation of the Tcl scripting language. This package contains the MSBuild tasks and PowerShell cmdlets that enable integration [with Eagle] as well as the command-line shell [for Eagle].
An implementation of the Tcl scripting language.
The Del Sole's VSIX library helps generating code snippets for Visual Studio 2015 and Visual Studio Code, plus it allows creating VSIX packages to share reusable IntelliSense code snippet files for Visual Studio 2015 and Visual Studio Code. We provide integrated Roslyn code analysis for live issue d...
Reference assemblies for Visual Studio Project System Extensibility
The Composition Analysis Tool (Mefx) is a command-line application that analyzes library (.dll) and application (.exe) files containing Managed Extensibility Framework (MEF) parts. The primary purpose of Mefx is to provide developers a way to diagnose composition failures in their MEF applications w...
An implementation of the Tcl scripting language. This package is built with options that make it more suitable for use with Mono. Features specific to Windows and/or the .NET Framework will be unavailable.
Additional classes and methods complementary too VSLangProj from Microsoft
Provides custom types, helpers and extension methods for Visual Studio extensibility, particularly its Team Foundation part.