Here is a simple bracket that makes it possible to build shelving racks out of T-Slot aluminum extrusion. All it does it mounts the extrusion at an offset such that it works as a smooth slide for organizers/containers.
I had some extra Misumi 1515 and some Stanley bin organizers I wanted to stack neatly, Adam Savage style :), so the STL is for that, but the design is customizable if you need to adapt it to other extrusions (1515 is not that strong tbh).
I recommend printing them out of ABS or stronger; PLA will crack more easily in such a setup.
For Misumi1515/OpenBeam (and the bracket included as a reference) you will need 2x M3 8mm screws and nuts to assemble each bracket.
I enjoy designing minimalist-functional 3D objects.