[Ankesh]

Stock Exchange. No crowds needed for trading stocks.

Similar example is Forex.

Writing.
Painting.
Drawing cartoons.

* Anything that can be "syndicated" allows you to work and make a living from anywhere in the world

* Or if the work can't be syndicated, then if you find a broker who can sell the things for you - you can work and make a living from anywhere

(For eg: there are quite a few people in India who live in villages that have a population of 200-300 people and create traditional Indian jewelry or clothes or pots etc. They don't sell their wares in their own villages. But rather, sell it to just 1 or 2 brokers who come to them once or twice every month. And these brokers than sell the stuff in big cities.)