Professional photography is of many niches like
and much more
Wild life photography is very dangerous yet have a good amount of money in it.
For nature photography u need to Travel around the world to get different different places to get the best shots and to get travel as well.
Cars photography is not that big field but it is a great habit of some people many people have projects cars for which they love to get photographs.
For celebrities it is in studios and on occasions but the angles matters the most which only professional photographers knows.