The type of format needs to contain the postmodern formula, and so some element of reveal and conceal needs to be achieved. The format below could work for a colour coded system where the designs are concealed inside the envelopes. The die cut element would show the colour but nothing else of what is contained. In order for information to be hidden, an interactivity aspect would be added to this kind of format.
Another idea would be to use postcards, that are small and contact. This could work well by storing different categories on each card, and gives an opportunity for them to be double sided. These postcards are held together by rubber band, though cards could be stored or hidden in envelopes or boxes, so this could be an option.
In another example, books could be stored in a box, layered up some kind of order. This could also feel interactive.