We really liked the “Small Shelf” (https://www.printables.com/model/154993-small-shelf) and wanted to mount a ‘Spinning Storage Hook Organizer - Under Cabinet or Shelf “Twirl Tidy”’ (https://makerworld.com/en/models/100124#profileId-106907) under it so we could put one on either side of our kitchen window because our kitchen cabinets are too low.
Unfortunately, the “Twirl Tidy” either hit the wall or hit the “Small Shelf” mounting brackets while spinning. This spacer moves the shelf out from the wall far enough for the arms on the “Twirl Tidy” to have clearance to spin. Plants on top within our garden window, measuring spoons within reach while cooking!
Nothing fancy, but maybe it'll save someone the time of measuring.
The author marked this model as their own original creation.