I have been searching for a mathematica package that can calculate the graph Crossing number of a (small) given arbitrary graph (the graphdata of known graphs doesn't help me). Before I write my own I'm checking here. My google searches returned methods to calculate it (or variants of the question) but didn't find any real implementation.
Geoffrey Exoo wrote code for finding (rectilinear) crossing numbers of arbitrary (small enough) graphs. I asked him last year about the possibility of reviving it from whatever retired hardware (floppies) it lives on. Unfortunately, I gather any such efforts have not (yet?) been successful.