This is not a SFW instance. NSFW communities will be tagged, and efforts will be made to keep SFW communities clean, but proceed at your own comfort level.
It is an HTML/JS pair, so it would require some wrangling to get it to write to a file instead of an HTML canvas. Though it looks like someone translated it to Python with file output here. (I have not tested this.)
Here’s one I know. Creates aesthetic wavy things.
https://tanck.nl/wallpaper/
It is an HTML/JS pair, so it would require some wrangling to get it to write to a file instead of an HTML canvas. Though it looks like someone translated it to Python with file output here. (I have not tested this.)