I needed to mount 6 - 120mm fans side by side on the front of the mining rig I built. I could not find any brackets that would hold the fans and then allow me to screw them to the face of the rig. I made these flush mount brackets. 1 set (top and bottom) will hold 2 fans together side by side. Photo coming with the brackets in use.

Note:

I would print them more than 50% infill. Reason for it is these were 20% and as you can see the screw heads crushed the surface a bit.

Also someone made a single: https://www.thingiverse.com/thing:2756758