I like the idea of the spring clamp hook of mscalora, but it holds the paper a bit away from the wall. If you just need it to hold a sheet of paper thats fine, but if you also want to directly write on the paper it gets problematic. My remix presses the paper directly to the wall.
I you wonder about the print quality in the pictures - yes I am using a cheap secondhand printer for this that I just barely got working. Model works fine, though.
The model-walls are designed to work directly with 3 layers and exactly no infill for the standard 0,4mm-nozzle settings in Prusa slicer. It fixes to the wall with a small screw. I just temporarily fixed it in a existing hole to try it out as I don´t know yet where it will go.
To release the paper you obviously only have to press the top.
I also did a model with a longer back, maybe you can just attach it with double-sided tape but I haven´t tried that yet.
Prints fine in PLA, might be better in PETG etc.
The author remixed this model.