Hobbies that can get profitable?

There are many hobbies that require you to develop the so called transferable skills: drawing, writing, programming and so on and so forth. It's usually easier to learn skills through activities you enjoy, especially because you pour more time into them without even noticing, and it's even easier to get good at them.What hobbies are the easiest ones to get into that can make you gain some money (even if they won't make you rich)? What are the most potentially profitable ones, instead? And…

Hobbies that can get profitable?