:P.S. I did take the list in WikiCommons and started transforming it into a gallery, see here, but the same story there. I did update in Wikipedia the article chart article and started some general articles such as mathematical diagram, network diagram, cluster diagram and Plot (graphics). Now I can really think of anything a separate list of diagram would solve here. I think this article needs more work, and some more specific general diagram articles would help to get a better understanding of the whole matter.