Extensions with .NET Standard MvvmCross solution templates for Visual Studio 2017 and Visual Studio for Mac. These extensions can create a native or forms project.
The solution for a VS 2017 extension is in .MVVMCross-VSAddIn.sln. To build this you will need the Side Waffle Creator extension installed (https://marketplace.visualstudio.com/items?itemName=Sayed-Ibrahim-Hashimi.SidewaffleCreator2017).
The solution for the VS for Mac extension is in MVVMCross.XSAddin\MVVMCross.XSAddin.sln