Any. Simple.

Subjects can range from academic subjects for school or university, to business and personal development like coaching, for example.

Say you have great experience in beer brewing and you want to be a consultant for people who want to start out brewing beer, that should be possible.

Say you want to share your knowledge and insights from your career as a salesperson, that should be possible. I'm not aware of any Bachelor's or Master's degree in "sales", are you?

So go find your best talent, gift or skill and start using that to generate an income from wherever you are, online, 1-to-1 via screen sharing and video calls. 

Good to know:
You cannot set an unlimited number of skills on our platform, only 3.