Codinion - Enhanced C# syntax highlighting. Symbol searchbar for better navigation in files.
CodeRush - DevExpress CodeRush for Roslyn uses significantly less memory, works faster, and lets you start Visual Studio faster.
ReSharper - ReSharper is a productivity tool for visual studio that provides tools and features to help you manage your code.
ReSharper C++ - ReSharper provides on-the-fly code analysis and eliminates errors in C#, VB.NET, XAML, ASP.NET, and XML
Productivity Power Tools - Extension for Visual Studio - A set of extensions to Visual Studio 2012 Professional (and above) which improves developer productivity.
Klocwork - Klocwork is a static code analysis and SAST tool for C, C++, C#, Java, and JavaScript.