Due to an oversized CPU cooler I had to give up my motherboard's PCIE1 (16x) slot and use the PCIE3 (8x). I wanted to keep the cooling performance on the CPU while maintaining the full speed (16x) for the VGA.
As I have a normal mid size case + a mATX motherboard format, I was aiming to use the standard ATX size's additional 2 mounting holes (in my case they are metric(M3)!) plus a 3.0 PCIE X16 Riser (~10€ from aliex. - i am not sure if I can share a link to the exact model here)
For the PCIE Extender there are 2xM3 threaded mounting holes.
Printed from PETG
Screws:
I am not sure if you need exactly the same as the there are so many variants of PCIEx risers but at least it might be a good starting point for ideas.
The author hasn't provided the model origin yet.