.NET developers: how clean up to 15 GB on your hard drive

I have a 128 GB Surface Pro 4, and I realized I had like 3 GB of free space left... mostly due to Visual Studio. It had VS2015 at one time, removing it to install VS2017 hadn't removed all of the VS2015 parts completely either. And removing VS2017 left tons of stuff behind as well.

Apparently every time I updated VS2017, it would go install the latest Windows SDK and .NET Core version, leading me to have a solid handful of each. The uninstaller seems to not be aware of all the various bits and bobs the installer adds, and doesn't even ask you if you want to remove them.

Careful with this, I believe if you target .net core 2.1 and you have 2.1 and 2.2 installed, and remove 2.1 then you're code will NOT run.