Top 20 NuGet extensibility Packages

Lightning fast MEF engine, supporting System.ComponentModel.Composition and System.Composition.
Extensibility library.
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.
Reference assemblies for Visual Studio Project System Extensibility
Visual Studio Project System Extensibility
Build tools used for building extensions to the Visual Studio project system.
Dynamicweb 9 package containing the Extensibility API
High-level, composable and testable APIs for working with IDEs.
An implementation of the Tcl scripting language.
Common targets to create version-aware Visual Studio extensions easily.
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...
Custom xUnit data attributes.
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...
Provides custom types, helpers and extension methods for Visual Studio extensibility.
A NuGet package which can be used to easily create item and project templates for Visual Studio.
Provides custom types, helpers and extension methods for Visual Studio extensibility, particularly its Team Foundation part.
The minimal set of dependencies to produce NUnit extensions and addins.
Static code analyzer to detect common mistakes or potential issues on the C# code that uses Visual Studio Project System APIs.
Deployment classes for Dropcraft, a NuGet-based deployment and application composition framework for .NET and .NET Core.
A tiny set of attributes + regutil exe to programmatically update the VS2010 IntelliTrace CollectionPlan.xml file, which let IntelliTrace use your custom events.