There are dozens of varieties of the venerable old Stainz. Almost every starter set has contained a Stainz, including the many 'collector/specialist toy shop' sets made for German dealers.
Also, with all the 'improvements' made in just the basic #2 Stainz, one would have a sizable collection. Carry these over to the #1, #3 and #4 models and the list skyrockets. From memory, #1 ceased in the mid-80's. #3 commenced in 1998, but has now been used again with the latest passenger set from Marklin. There was also the cab colour variations in all the basic models as well. I certainly would not embark on such a daunting adventure.