I was looking for some “Stehordner” that can be customized and couldn't find anything, so I came up with this first draft for the Quarter Horse Journals as a proof of concept.
Not yet perfect as I tried to use two colors and therefore printed so that the vertical side was on the plate to have the least amount of filament changes but that had an impact to the “bridge” on top then….
Further, the calculated filament costs are at ~ 6€ which makes it more expensive then buying a magazine file from an Office Supplier shop but that wouldn't be the same fun as creating something from scratch ;-)

The model was created in TinkerCAD