You can use the circles you make as part of a creative work that is for-profit. You can put it right on the cover and sell a trillion copies with no problem. You can generate millions of images and use them in a game with no problem.
I'm mainly concerned with preventing people from spamming itch, game dev market, and other platforms with asset packs like "2000 unique magic circle asset pack" and I don't want anyone to scam people with "Magic Circle NTFs"