Many hundreds of medals with Hitlers image on them were produced between 1920 and 1945. The were in Gold, Solid silver, Brass, Bronze. Copper, Zink and Plated metals.
Well, that's certainly a factoid (haha). What do you have in your collection?
If you look up the book by Colbert and Hyder. The metallic Portraits of Adolf Hitler. You will see what they knew about in the 70’s. However with the advent of the internet many more have come to light. I have about 90% of the C/H Book and about 75 others, including some plaques and many stickpins.
Fascinating! I have seen the book, but don't own one. How long have you been collecting?