There are some more with low production numbers:
Bergetiger
Churchill Avre
Churchill Crocodile
Calliope
FG 42s
Yeah but the AVRE and Churchill croc served very specialized rolls, often being assigned to combat engineer units. All of Hobart's funnies served well in the Normandy landings because they were engineered to meet a specific problem.
Where as the bergetiger was pretty much useless and only good for pushing wrecks off roads/or pulling tigers from natural VCAS. The FG42 was all around a failure of a weapon by combat standard as the weight was so horribly skewed and the calliope wasn't as usefull as self propelled guns which serve the same purpose and have a lower profile.(also have you ever tried loading 60 rocket tubes... screw that.
And yes Stumpster fewer were made, but AA tanks in general are fail, as it's armoured formations that planes strafe