[Marcello]

Disclaimer
I am going by memory here so take what I say with some caution.
Most of the vehicles belong to the E series.This was a german scheme to rationalize the mess that was late war AFVs production by replacing most of the vehicles then in use with a single family, ranging from 5 tons APCs to 100 tons super heavy tanks.These vehicles were characterized by a great degree of components standardization (IIRC for example a single type of roadwheel was used for all vehicles) and particular attention was given to easiness of production (the suspensions were MUCH simpler to make than previous models). As I said there were vehicles to cover all the roles:
E100 100 tons Maus lookalike;
E75 75 tons King Tiger lookalike;
E50 50 tons Panther lookalike;
E25 25 tons tank destroyer;
And so on.
In most of the cases they did not get beyond the "half completed prototype lying in the factory" stage, if the got that far.There may have been a Marder or a Nashorn lookalike completed and pressed in service but my memory is a bit fuzzy on that one.
Hard data is scarce (or at least it was when I did my research).There are some stats around for the E100, the E25 and some of the lighter tank destroyers.I found very little about the E50 and the E75, to my frustration.