Unfortunately lots of stuff runs under there including, but not limited to:
GitHub for Windows and dozens of apps it installs in there
F.lux
Anything installed with ClickOnce
Chrome
GMVault
Xamarin's Android Support
Markdownpad
SkyDrive
Join.me
Assuming that everything in there is a virus is too much, I think.
I would think that .Net portable apps are likely also per user executables.. not to mention that there are usually at least one scripting environment even on windows cscript/jscript/vbscript/powershell for example, not to mention Java, Python, Ruby and/or node may be installed.
GitHub for Windows and dozens of apps it installs in there F.lux Anything installed with ClickOnce Chrome GMVault Xamarin's Android Support Markdownpad SkyDrive Join.me
Assuming that everything in there is a virus is too much, I think.