Simple, but eminently useful. Many aspects can be customized, making the the hanger a perfect fit to the hangee. Print, push together, and mount.
No screw holes option exists as far - I use strong two-sided sticky tape, and am considering an alternative mount option using (printed) brackets. Though I might just a well add an option for adding flanges for attaching using screws (done in v0.0.2)

Easy print - no supports, no special demands to base layer adhesion. I suggest to print a single bay and hook first, to adjust the slack parameter if necessary.

OpenSCAD source provided. Customizer. It's on you to use reasonable values, as customization doesn't check parameters for plausibility.