This is to be used with a cheap display cabinet I found on Amazon

https://www.amazon.com/gp/product/B0C6ZD75TP/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&th=1

Originally I designed a rack that needed NO bracket but they broke after a couple months of use.  This design uses the included brackets for the shelves and I “back-engineered” my own version of the clip which I printed from PETG and they have been holding fine.

Crossmember print: 4 perimeter walls, 15% gyroid infill

Bracket print: infinite perimeter walls or 100% concentric infill/infinite perimeters 

The rails are just painted ¾ PVC pipe.