Both online and offline media just seems to grow and grow, and with that growth comes an increasing need for content. Whatever your knowledge, experience and expertise, it’s likely that someone somewhere will be willing to pay for you to commit some words to pixel or paper.
For example, I just read about an astronomer who makes a regular second income writing for various astronomy and science based magazines and websites, and a photographer who provides articles on cameras and photographic topics to media in that field. You don’t have to be a world expert to make money like this, but just need to be able to write clearly, interestingly and with a bit more knowledge than most.
If this interests you, try contacting the relevant media in your field of interest. You may be pleasantly surprised by the positive response.