Orange PI Zero case with FAN and side antenna holder (Source Fusion 360)

thingiverse

To assemble this case securely, four M3 screws are required. This case is specifically designed for use with a 25*25mm fan. To attach the fan properly, you'll need to apply hobby glue or melt some of the same plastic used for printing the case. Simply take a piece of that plastic, heat it up with a lighter until it's melted, and then add small drops of the melted plastic to hold the fan in place. This product was printed using SBS plastic, as seen in the accompanying photo.