Just to save time in the future, this search string for Windows Explorer can be used on the root Amazon Drive folder to find all non-image files:

NOT *.raw AND NOT *.jpeg AND NOT *.CR2 AND NOT *.jpg AND NOT *.dng AND NOT *.tiff AND NOT *.png AND NOT *.CR3 AND NOT folder AND NOT *.tif AND NOT *.xmp

(remove AND NOT *.xmp for the correct value, but those tend to be tiny)