A simple support for plates printed in place using 1 layer as the hinge.

2 models available. 1 for very small plates and one a little bit larger for bigger plates.

Print flat with 1st layer at 0.25mm. Prefer PETG as it is more flexible but PLA can also be used but with higher temps so that it does not print brittle.

You could also remove the top layer to show on the outside the pattern of the infill:

You can scale these but in your slicer make sure that the first layer is 0.25mm (use either slicer split tool or move print slightly under the bed so that this height is reached)