I really like these little PiZW cases by swintera: https://www.thingiverse.com/thing:4708460
But I wanted a fan.
So first I printed some variants and drilled and hacked and got something that would work, but I really wanted it done better/nicer/cleaner.
So I remixed it, learning OpenSCAD at the same time.
Then I got fancy with parameters and logos and text.
Anyway, you need the plain face from the original, and you need to fix it through whatever means you have to avoid weird OpenSCAD errors. All files need to be in the same directory/folder, or you'll get errors.
There are some comments in the .SCAD that might be worth reading if you're fiddling, particularly with text and logos.
I used these 30mm fans https://www.amazon.com/gp/product/B07QH9M6QD