Botswana, Canada and Indonesia are the ones that I have been to so far.
Namibia, Tanzania and possibly Zambia if you are the right person for the job (Ignore the doom sayers that tell you 1000hrs. The right people will get a job).
Northern Aussie amongst a few other places there but those jobs are pretty hotly contested these days. Still though, with 500hrs you will have a bit of a leg up.
Papua New Guinea is usually pretty good if you make a few visits, knock on some doors and talk to the right people while making a good name for yourself.
There is also a few worldwide survey type jobs as well. Some of those companies have a massive turn over of f/os as the flying is boring, lots of crap countries/hotels and they work you pretty hard.
The internet is your friend. Sit down and use it for a week or so researching most of the developing countries or the big GA countries where you can easily get work visas.
Ask knowledgeable people for advice, build networks, and do your research. Don't expect anything to be spoon fed to you or dished up on a platter.
All it costs you is your time and will launch your aviation career in a matter of a few years. I left NZ with 500hrs. After 3 and a half years, I'm nearly at 3000hrs and have the ability to pick and choose where I want to go.