I like it, it's like paid leisure, and the more you do it, the most likely you already have something that almost does exactly what they want and just needs a few changes.
I wouldn't know where to start looking for clients though.
If you don't mind me asking, which kind of organizations are usually interested in your work?
For me it's usually smallish organisations, startups, sometimes associations, who want a map that looks better than a run-of-the-mill Google maps with plain markers, really. So they see something like https://ssz.fr/voies/ or one of the variations of https://ssz.fr/territoire/ and ask for something like it that shows their data in an adequate way (and hopefully a good looking way too, using their colour scheme, etc).
After that they sometimes ask me if I'm available for more map-related projects or iterative improvements to the first maps (and I am as long as they're small enough projects which won't take me more than a week or two).
I think larger companies just don't email a random author after they find their address on a map, but that's fine because they're less interesting to work with in my opinion.