People on Artstation and other portfolio sites create these personal projects full of astonishing worldbuilding, but they've got no framework for implementing their worldbuilding. Even if they know RPGs exist, they might not have the skills, contacts, experience, or time to adapt their work.
People in the DIY RPG community have plenty of experience producing, publishing, distributing, and writing books, but (often), not enough cash for lavish art. Sometimes they also lack artistic inspiration.
Two groups of two people. Two eminent compatible passions.
The only project I can think of that started as art and became an RPG is Tales from the Loop, which started as Simon Stålenhag's disconnected art pieces, became narrative art books, and eventually had an RPG adaptation.
So if you see someone build a world with superb art, and you think you've got the skills to execute a project successfully, see if they're interested in creating an RPG, setting guide, or bestiary from their work. I'd suggest including non-exclusive rights (so the art and ideas can be reused elsewhere if a better offer comes along) and fair method of revenue sharing. Maybe the artist says no. Maybe they ignore you. But it's worth a shot.
Full RPG systems are ambitious and difficult projects. Writing a complete system requires a very specific skill set and a lot of playtesting. Setting-neutral material is tricky to create but can be much more rewarding.
Right now, Nicolas Folliot (twitter) is potentially working on some sort of RPG adaptation of Lucas Roussel's Le Monde de Rouille setting. I don't have all the details but it seems very exciting.
original setting is in French. If you can read French, great! If not,
OCR + translation software is so advanced these days that it's a matter
of minutes run the images through a few programs to get the gist of the
With Lucas' permission, I've created an unofficial free 29-page
bestiary and random encounter table for the "L'Exante" / "Era of Ruins"
period. It's a great sci-fantasy / sword-and-planet / Ultraviolet Grasslands resource.
Translations are my own. My French is good enough that waiters
in Paris look at me like I've spit in their coffee, then speak very
slowly to me in English, waiters in Belgium laugh and call their friends
over, and waiters in Quebec call the OQLF to arrest me. You've been warned.
Images have also been lightly edited and whitepointed for easy printing.
bestiary is just a list of monsters, plus a massive d120 table of Omens
and Encounters. To roll a d120, use a d12 for the 10s place and a d10
for the 1s place. No stats are provided.
There's also a GLOG-style d20 table of races.