The Productivity Power Tools were first released in 2010. They are pack of powerful extensions to improve developer productivity. This free add-on has been downloaded more than half a million times in its various versions, and since their introduction these tools have been updated for every major Visual Studio release. Over time, many of its features have been merged into Visual Studio.
Who knows what Microsoft will do next with Linux and open source? Personally, I'm betting on Exchange Server running on Linux. But, who knows, maybe Microsoft will open source Visual Studio first. After all, this is Satya Nadella's Microsoft.