Microsoft Refresh Windows Tool allows Windows 10 users to refresh their Windows installation as well as perform a clean installation.
In its current state, it's hit or miss as to which version of Windows 10 it will run on. Leave it to Microsoft to break the entire purpose for the program's existence.
If you're looking for Windows 10 or the media creation tool, that can be downloaded here.
Limitations: During the beta, it will only work on recent Windows 10 Insider Preview released builds (build 14342 or later).