[Marcello]

Personally if there is a terrain that I missed that was some sort of sand berms that could be laid like bocage hedgerows. That would be very useful for iraqi maps.
Next a SPWAW style wall.
I also used to miss some sort of concrete like terrain that could be used as pavement above the zero level, as well as for structures like dams and such. However I found out that grey sand was a decent enough surrogate.