This is a remix of the "1U Half-rack Shelf (1 Post)" by rqdsvw (https://www.thingiverse.com/thing:2114676) .

I used MeshMixer to cut the model in half, then exported to STL.

I found I couldn't fit the half rack on my print bed and decided I only needed a quarter width for my raspberry pi and relay setup. You could throw a cable tie through the vent holes to secure anything in place.

One thing to note is that the plastic wings are thicker than a traditional metal rack mount appliance so you will need screws that are on the longer side to thread into your rack nuts.

Works well at 25% infill for the weight I was putting on it.