What freelance markets exist apart from webdev and mobile dev?

After a 5-year break, I'm looking to get back into freelancing. I used to be a webdev freelancer, but it seems the world has moved so much ahead in these 5 years that webdev is far from the only option for a freelancer. Since I'm not interested in getting back into webdev, I'm curious to know what other options exist for modern tech freelancers?