Raspberry PI 3B case with space for 40x10 5V fan Noctua NFA4x10
Free     Printables     PCHe

Raspberry PI 3B+ case with space for 40x10 5V fan Noctua NF-A4x10

All Raspberry cases I have found were small fancy without possibility to mount a fan So I have made one models ...

similar models —

Raspberry PI 3B+ case with space for 40x10 5V fan Noctua NF-A4x10 alternatives
NES Raspberry Pi 4B case
FoxResearchAndDevelopement