While it is very easy to create Metro Style Apps using Visual Studio while programming in VB, C#, JS, HTML, C++ & etc. A great deal of investment has been done by Microsoft in providing rich controls which glorify the beauty of Metro Style Apps.
It is really upon the creativity of a developer that how he/she leverages and various customization options by living in Visual Studio & Expression Blend environment.
Although you would nearly find all XAML controls in the toolbox but some of them which you would be regularly coming across and would be creating more impact to Metro Style Apps can be (visible in picture 1), Grid View, Flip View, App Bar, Panning Indicator, Toggle Switch, Rating, List View & Progress Bar etc.
Keep creating state of the art Apps! a big market is on your way…