I designed this to string up Christmas decorations around our 10mm recessed ceiling borders but with a bit of tweaking you could use it pretty much anywhere you need to hang stuff that isn't too heavy.

NOTES:

• With a single cooling fan I got way better adhesion aligning the part perpendicular to the airflow.
• If you're only printing one then go slow, or make sure your minimum layer time allows for enough cooling between layers. Once I got the design nailed I just did a batch of 20 in one go.
• The included Fusion 360 file also includes an earlier version with more aggressive teeth that may grip better in some applications, not parametric but easy enough to adjust the sketch if you need to.

MY PRINT SETTINGS: (Definitely some room for tweaking but this worked for me, approx. 4 minutes per hook)

• Printer: Ender 3 S1 Pro + Sonic Pad
• Nozzle: 0.4mm brass
• Filament: Creality PLA (black)
• Temps: 195° / 60°C
• Speed: 50mm/s
• Line width: 0.4mm
• Layer height: 0.2mm
• Top/Bottom layers: 2
• Walls: 2
• Infill: 40% Cubic