There are a lot of door hooks here on printables, but they are mostly weak, and tend to break if you hang multiple things :) 

I have designed my own, that is strong and can hold more weight.

Printed with the Creality White PLA.

It takes about 1 hour and 14 grams to print. 

Some slicer settings I used, and recommend:

• layer 0.2mm
• walls 1.2 mm
• infill 20% 

no support, no adhesion, prints easily on glass with no glue :)

Feel free to ask any questions or suggest improvements. 

You can find hook dimensions below: