As I was fed up with the mess of different cardboard boxes and rolls stacked on top of each other, I built myself a box. After various versions, I have now arrived at the one published here. It offers the option of inserting a colour plate so that you can immediately see what it is. You can also insert printed cardboard for more details. I chose the width so that almost all 1kg rolls (Sunlu, Bambulab, Prusament, Eryone and many more) fit in and 10 boxes fit on an IVAR shelf.

For special filaments such as Prusament Mystic Brown/Green, where the appearance differs with different settings such as the layer height, I have also built a version where another plate can be inserted at the back.

One box uses about 270g of filament, so you can print 3 boxes from a 1kg roll and still have a small leftover for e.g. a color plate, Temptower, Benchy or something like that.
Due to the color plates, the boxes are reusable and can also be printed from leftovers.

The dimensions for the colorplate are 73x73x1.8mm, for the paper inserts (I recommend 200g paper) 72x32mm.

I started with generic colorplates without text, which were printed horizontally. Now I generate my own plates for each filament and print them upright, which looks much better.
I used the plates from https://www.printables.com/model/27814-filament-swatch in an older version, resized them and adjusted the texts and positions.

You can find my Plate-Version here.