One of the favs that I have is the Argentine OS for the Spanish language version of
The Criminal Code - El Codigo Penal (1931). I think because, I realized that this movie also paired up the 2 actors who also were in the Spanish version of
Dracula, Carlos Villarias and Barry Norton and filmed only a short time later. So that was pretty cool, IMO. Plus it represents that small number of years (and films) in film making when dual language versions were shot, rather than the English version being dubbed.
And the chances of snagging a Spanish Drac OS are, well, in need of some
(and $$$$$$)