I would like to display the view in the folder if no controller/action matches.
For example www.site.com/Home/Index, if I have the normal default route {controller}/
I came across the same issue recently while developing AJAX web applications where most of the pages don't actually need a controller (all the data is returned via Web API calls).
It seemed inefficient to have dozens of controllers all with a single action returning the view so I developed the ControllerLess plugin which includes a default view controller behind the scenes with a single action.
If you create a controller for your view, then MVC will use that. However, if you create a view without a controller, the request is re-routed via the default plugin controller.
It works with C# and VB.NET and us available at https://www.nuget.org/packages/ControllerLess
The source code is also available on GitHub at https://github.com/brentj73/ControllerLess