In the Windows 10 Technical Preview released this week, you must have noticed the direction in which Microsoft is driving the desktop UI. The UI is going to be more flat looking to match the Modern UX environment. Even though the icons in the technical preview build are still same as in the Windows 8/Windows 8.1, no.of flat looking icons were spotted in the system folder. Take a look at the icons above, Microsoft is redesigning all the current icons to have flat minimalistic look which I think is pretty.
If you are interested in the Icoms that came with windows Technical Preview you can download theme from here:
Download All Windows 10 new Icons