Loaded Projects is a Visual Studio extension that helps you manage very large solutions. Even with the improvements in Visual Studio 2012, you will generally find the edit/build/debug cycle is much quicker the fewer projects you have loaded.
You can create one or more profiles that represent a snapshot of the current unloaded projects.
Then you can easily switch between these profiles, if you're working on different parts of the solution.
See https://david.gardiner.net.au/2013/03/loaded-projectsa-visual-studio-extension.html for an overview.
v2.0 - Add support for 2017
v1.5 - Progress count, preview image
v1.4 - Bug fixes, progress dialog
v1.3 - Save and load profiles to XML file
v1.2 - Handle unusual solution items better, fix saving/loading profiles
v1.1 - Add custom icon, edit profile names when saving
v1.0 - Initial release