https://www.printables.com/model/558873-zettelkasten-index-boxes-slip-box
Someone has designed a DIY printer project for making your own stackable zettelkasten boxes.
See post at https://www.reddit.com/r/Zettelkasten/comments/15wkuel/zettelkasten_index_boxes_slip_box_make_your_own/
The Wörterbuch der ägyptischen Sprache was an international collaborative zettelkasten project begun in 1897 and finally published as five volumes in 1926.
https://en.wikipedia.org/wiki/W%C3%B6rterbuch_der_%C3%A4gyptischen_Sprache
In the research phase, you’re just creating a disorganized pile of cards, with quotes, ideas, links, fragments, hunches. There’s no order, no sequence; just a non-linear collection of vaguely related ideas. But as the project takes shape, certain themes begin to emerge, and those become folders housing other cards. Eventually those themes start to map onto actual sections of the book, or individual chapters. At this point, sequence does begin to matter, but you can change the sequence just by dragging cards and folders around in the left hand outline view.
Example of writing advice that builds the links in after-the-fact instead of cross-linking ideas into initial networks as they're finding them. Compare/contrast this to the creation of these networks in the zettelkasten tradition as well as Sönke Ahrens description.
There's less upfront work in creating these links at the start than there is in reloading the context in one's brain to create these links after the fact. Collecting ideas without filing, linking, or organizing them upfront also means that one is more likely to only use these ideas in the context of specific projects which one already has in mind rather than keeping them for a lifetime's work which might also create generative projects one hadn't expected.