This is a custom hook for Tiny Team mini dustpan with brush made by Full Circle.

I measured the ring on the brush and on the pan then modeled it in Fusion. I designed the hook and then cutout the shape of the pan/brush handle for a perfect snug fit. It is mounted on the inside of our sink cabinet with a 3M strip and it doesn't budge a bit when we open and close the door.

I included an STL of the broom/pan ring as well.

I opted to place the brush in between the door/wall and the pan so that everything tucked close to the door.

I printed in a semi-matching gray PETG.
 

Notes:

Lay it on the skinny side rather than on its back.