The intellisense is named intelliclunk in Rhino for a good reason 
But just because a module doesn’t show up on import doesn’t mean you can’t use it. Unfortunately the help("modules") method doesn’t work in IronPython for listing all available Python modules. But you could do something like this to get an overview (note that this won’t list the available .NET libraries):
200417_GHPython_GetIronPythonModules_00.gh (4.6 KB)
Can you post a screenshot of the error messages that you get?