This is an easy to print (no support needed) modular case, however, it's mostly suited for DIY projects, if somebody wants to use it just for media PC and ignore the Raspberry Pi header, then probably other cases worth considering. This was designed mainly to allow flexibility for users who want to connect devices to the pin header, in my case it's an ICE40HX FPGA board called iceZero.
All holes for connectors have fairly big margins so even thick cables will fit. And overall it has plenty of holes for good ventilation (including the underside of the PCB). All the holes do not cause large bridges for the printer to breach and it should be printable without issues without any support material.
The base has a gap between the bottom and PCB and it will fit small heatsink even on the RAM chip. So even the bottom side is kept cool.
The base is designed for threaded inserts such as these:
An M2.5 insert with 3.8mm outer diameter. The hole is going through the whole bottom, allowing to add second insert (or one long) and screw the case against something else (mount it on the wall, etc.)
The bottom part has various variants and it differs how much extra space is between the PCB and the top (measured in mm).
If your project evolves over time and the original size is too small then an addon module can be printed to extend the height (they will stack up on each other). It's better to flip this addon model by 180 degrees in X-axis for easier printing. The overhangs are 45 degrees and only a few mm big, so it should be fine to print without any support (I'm always printing them without the support and had never any issues).
The top/cover model has various designs with vents for fans, or without fans, one design is made for 60mm fan which can be mounted on the outside or inside (the inside will just perfectly fit a 60mm fan, but nothing bigger). And there is one variant for various fans with many holes in the hope some will fit your fan dimensions.
If needed all these files can be tweaked (parametric sources included), but if something specific is needed I'm very happy to supply it, just leave a comment with a request.
The the/cover has holes for screws, which are slightly counter skunked, so it will not scratch other things when carried in a bag and so it will allow for the top to be screwed in, whole allowing a fan to be screwed on top of it (without interference with the previous screws). This feature creates an overhang of 65 degrees and is few layers big, so I shouldn't require support, because is so small for some screws this might have to be enlarged manually in post-processing with a drill or file.
The top/cover model has matching holes with the base so when long standoffs are installed (or long screws used) then the top can get screwed into it directly. If screwing it in is not an option then it's possible to use a small dap of glue to make it fixed (while no making it fully permanent). Another option is not do anything, the top does friction fits on the bottom model (or on the addon model) and for desktop projects that can be enough protection and should stay together under normal use. There is a 'lip' feature which does friction fit on the bottom/addon and fixes the top/cover in three degrees of freedom anyway. For a permanent enclosure, any generic glue can be used, as the 'lip' increases the surface area as well and should form very strong (permanent bond).