Updated version of ssvenn's Raspberry PI PCI adapter, and makerschrott1 "upside down" version but remixed for the Raspberry PI 4B.

I wanted to mount a Raspberry PI in a server in my rack, so I didn't have it taking up needed space somewhere else, with help from konstantin_p on fiverr, a POE hat, and small fan 3M taped into place this fits the bill perfectly!

I didn't know which orientation would fit best in my case so we created both left and right mounting versions, as well as a "combined" if you want to print both and figure it out once you get it printed), the mount itself is probably roughly 1.3~ PCI slot widths, but I could see putting multiple PIs in the same case if you have the PCI slots available.

As for preparation, ssvenn's instructions still apply: "Carefully bend the bottom of the bracket outwards a bit, it makes it easier to find the guide slot in the PC case when installing. Make sure to remove all support material from the hole for the ethernet cable, it's a tight fit. Depending on your case, the two upper USB ports will probably be blocked after installing. Also take care not to apply too much force, the plastic bracket is quite flimsy due to only being 1.2mm thick (you can increase the thickness in openscad but any more wouldn't fit my tower)".

I did have to trim down the bottom (foot?) of the PCI bracket by a mm or so the thickness to fit into the retention slot on my case, but that may be just an issue with the tolerances expected by my case rather than a design issue.