If you're looking for a real estate career that not many other people have discovered yet, unclaimed overages are where you should start. Unclaimed overages are funds being held by the government that belong to private citizens. These people, for whatever reason, have lost track of these funds and stand to lose them if they aren't collected in time.
If you decide to become a "found money" professional, you may be tempted to start with state-held funds. These are the funds you can find on states' "treasure hunt" websites, and usually come from things like stock dividends and utility deposits (i.e., aren't for very much money). Unfortunately, you'll never make much with these unclaimed overages. They are too visible, and too small in amount to make much money - these funds are capped out by state law at a 10% finder's fee.
The unclaimed overages you need to focus on are those created by real estate - tax sale overages, mortgage foreclosure overages and the like. These funds run into the tens of thousands of dollars, and due to a loophole almost no one has yet discovered, are NOT subject to the same finder fee limit laws that state-held funds are. That means 30-50% finder's fees. On many thousands of dollars, that's a hefty paycheck. They also aren't advertised online... so people you contact will not be able to check and find the money on their own.
Something else you'll probably like about unclaimed overages is that collecting them can be done entirely from your home office - online and through the mail. You can find records, find owners, contact owners and process claims all from your desk - whether it's in New York or New Zealand.