Microsoft’s startup program is called BizSpark. If you need some starting help into Microsoft’s ecosystem, apply for BizSpark right now.
Syncfusion is another provider of awesome controls for your Windows and Windows Phone apps. On top, they provide their icon program ‘Metro Studio’ with more than 2500 free to use icons. They have also a pretty awesome e-book collection, each of them available for free!
Xamarin provides an easy to use IDE to develop Android and iOS apps in our favorite programming language C#. The tools also integrate nicely with Visual Studio. If you need to develop cross platform apps, Xamarin is your number 1 address to go to.