I have a side hustle where I produce niche desk ornament sculptures and busts made from concrete. Etsy link: https://www.etsy.com/shop/jurgenstudio
This brings me around 500 euros per month. Recently the sales of Marcus Aurelius took off nicely, so I'm seriously thinking about expanding this business by making busts of more famous philosophers and leaders. I'm in the process of adding mini concrete busts of Alan Turing, Steve Jobs, Slavoj Žižek, Nikola Tesla, Plato, Aristotle, Jordan Peterson and more.
If anyone is interested in how I these are made (3d printing, molding, concrete pouring), please check here: https://twitter.com/matixmatix/status/1243116129289146368