I have an ATP an recently decided that I want to experience work outside of the USA.
Well, if you want to work outside the US the question is do you have the legal right to live and work in the respective country? Without a work-permit, this will be quite difficult if not impossible to achieve (e.g. the EU). Unless you're a highly experienced pilot/Captain with several thousands of hours on an Airbus or Boeing and intend to work for some Asian carrier, since they are frequently looking for experienced foreign pilots.
However I would like to know what coutries can I work without converting my license?
General speaking, one must hold (convert to) the respective national license in order to fly commercially or the respective license in accordance with the aircraft registration. Which you have already mentioned in your last sentence, meaning N-reg aircraft = FAA license.