This is a replacement for a broken bracket for a shower cubicle door runner (I don't know the make or model, sorry). 
The door is curved glass, and the runner assembly will allow the runner to move left and right on the screw it's attached to. The runner assembly, screw and nut are all salvaged from the original broken assembly, and are metal with bearings and plastic wheels.
As you can see from the pictures of the original (the chromed one), the plastic has sheared off at the point of attachment to the glass, so the runner is no longer attached to the door.

I've printed the current iterations of the design in PLA, which should last at least a little while. I'll probably reprint them at some point using PETG or ABS, or maybe ASA

Print orientation: I printed them with the long side on the base of the plate. If you print it upright, the layer lines will be in the same orientation as any stress put on the part, so I'd avoid that if possible. This did mean that supports were necessary.
I may try to print it on the long side, to see if supports can be avoided completely