The French also manufactured a rimless-grooveless 9 x 19 mm Parabellum cartridge, type “Auto Frettage.” I have a specimen with no headstamp, although I understand there are others known with headstamps. I have never been given a explanation of “Auto Frettage” (the use of them) that I fully understood, but think these were for a text fixture of sorts rather than for any use in an actual firearm.
If one includes plastic cases, there are also rimless-grooveless .45 auto rounds, purely experimental I believe, that were made by Winchester. I have samples in several colors of plastic cases, the one most often seen, I think, being red. I don’t know what there intended use was.
A caution. In some draw sets, there are basically finished cases other than the step of milling the extractor groove and extractor-groove bevel. One of my rarest 9 mm “cartridges” is one of these draw-set pieces, not actually a finished case. It is with the Cameroon headstamp “MANUCAM 9” and is copper-washed or copper-plated steel. The case was probably made in Germany, likely by MEN. I have never seen another example of this headstamp on a copper-coated steel case, although it exists on normal, brass-case ball rounds.
This would NOT count as a rimless-groovless cartridge case.