I designed a simple door handle during COVID-19 lock down. After my kids slammed the kitchen door against the radiator a few times, I had to glue the existing handle again and again. I didn't feel like installing a door stop (also, shops were closed) for this old door that will be replaced at one point in the coming years. I did feel like creating a replacement object...
If made a design with OpenScad, but after rendering it as an STL file, I had to post-process the file using Meshlab's "Filters -> Cleaning and Repairing -> Merge Close Vertices" to be able to slice this with PrusaSlicer (Import the stl as mesh, apply the filter and use export mesh as STL again).
I printed the object laying down, and I didn't use supports for the screw and nut holes, going through the hole with a 5mm drill to clear any overhang malformations was enough.
After that, I could insert a M5 nut into the hole, and pull the nut into its place by inserting a screw. It's best to the screw pull against a small piece of metal, like a second screwdriver, to avoid its ending up pushed into the plastic. Be careful not to over-tighten, the plastic may crack.
I was careful with infill in the part that mates with the door to avoid cracks there, I used 4 perimeters and more (selective) infill there.
For now, you can find the files on thingiverse.