If you aren't allowed to, or simply don't want to, screw into the wall, I've made a nail-in wall mount with a female dovetail slot. Simply nail this plate to your wall, and print whatever attachments you'd like using the male dovetail component. The nails are angled 45° for greater strength, similar to picture hooks. I've tested it up to 200g in PLA and it holds fine.

• Nail hole diameter: 2mm

• Dovetail outer dimensions: 5mm thick x 40mm tall

• Dovetail width: 17mm tapering to 10mm

• Dovetail tolerance: 0.1mm

• Female slot outer dimensions: 20mm wide x 45mm tall oval