I have been searching for a decent Croatian locale for magento 1.9 but so far nothing. Could you recommend something?
You can find here a lost of all locale packages.
They are from 2 years ago and they were all downloaded from the magento commerce website when it worked.
I know they are old, but at least it's a place to start.
In addition to that, you can use this extension that will help you isolate the texts that require translation on module bases.