A couple of years ago I identified over a 100 different items available - although some were just the remaining stocks of older designs.
You mean collectors' items.
Here is the audax equivalent of a misprinted penny black -
I think only 2 of these were struck, Keith Benton may still have the other one:
The above was the manufacturer's sample before the production run for the year 2000.
The actual production was not finished in gold though:
Even these are quite rare as the monochrome medals were only issued for 2000,
for 2001-2003 the production reverted to the usual coloured type: