There is a murder of crows, a congress of owls, a charm of finches, a convocation of eagles, a labor of moles, a murmuration of starlings, and so on, but there is nothing for a group ("knot"?) of lawyers, or a collection (a "slick"?) of politicians...or for that matter a grouping of skeletons. Perhaps when you have a grouping of ten or more skeletons (standing and non-interred) they could be called a "Mall". They should be called something, I guess. But of course one wouldn't have many opportunities to describe a mall of skeletons, though one opportunity presents itself right now: in my experience of looking at antique scientific and medical images it is not very often that I have seen such an assembly as in the following image.
The skeletons are mostly in poses of some sort of relaxation, appearing in candid stances, far away from that of being in the anxious state of being a skeleton. Most of the skeletons have some degree of skin-in-outline, and a few entertain themselves with a casual object, like an apple or a plumb bob. (The two figures in the rear seem to be having an "I told you so" sort of conversation, with the sitting person making the point and the standing refusing it:)
The engraving (which is the top half of the full plate engraving seen below) is from Crisostomo Martinez (1638-1694), an Enlightenment figure from Valencia who produced a lovely anatomical atlas that really wasn't terribly "Enlightenment-y", what with a deluge of unnecessary characterizations and Baroque decoration serving as miniature cartoons from one anatomical image to the next. That said, the images are quite beautiful, and creative, and imaginative, and clear, and concise...but perhaps not as detailed as they could be from the anatomical side.
The assembly of loose bones on the bottom half of the engraving is interesting but not as useful as it could be--close-ups would be nice for the details in the nicely-sectioned bones. But the purpose in these illustrations wasn't necessarily just the presentation of anatomical information, otherwise we would have had less nothing and more something. Making visions of thinly-skin-clad skeletons certainly had its use and a good purpose, but a lot of the utility of these investigations is lost in the artful and beautiful presentation.