I notice that the diagrams are drawn with Fritzing but I have also noticed that Arduino use a few components that are not in the core components. Looking at this diagram:
The ceramic capacity with 3 pin range and the crystal are not standard as far as I can see.
I have found the crystal but the only ceramic caps are the blue ones that span 2 pins not the flat ceramic discs. The blue ones don't have the low values I want either ie 4.7pF etc.....