After a lot of try and error i figured out there is a lot more than rhinoscriptsyntax.
import rhinoscriptsyntax as rs
works only for one item not a list.
import ghpythonlib.components as gc
works for list of items because these are grasshopper components.
Also import Rhino works (very powerful).
I only was missing some grasshopper components in ghpythonlib.components like BrepContour but with Rhino.Geometry.Brep.CreateContourCurves(brep,point,point,distance)
it works also (found this example from Helvetosaur thanks).