Paper Modelling (October 2021 Cartographer's Annual)
The Mapping Guide for the October issue of the Cartographer's Annual has some excellent notes on preparing and constructing paper and card models for use in tabletop gaming, aside from describing the models provided with this issue and how to customise them for individual use.
Two paper model manufacturers were singled-out for particular attention there, World Works Games and Fat Dragon Games. Both have indeed been producers of excellent quality downloadable PDF models, and both have construction information provided with some of their products and separately online. However, there's an unfortunate past tense here.
Fat Dragon Games is still a going concern, but the owner has switched attention entirely to 3D printed models in the last few years, so while the paper models back-catalogue remains fully available, there have been no fresh models during that time, nor does it seem likely now that there will be. Fat Dragon's products are available directly from the company's website, as well as via the OneBookShelf download sites (such as DriveThru RPG).
World Works Games too still have much of their old back catalogue available online, but only via their own website. For unclear reasons, the owner stopped supporting the site some years back, and has produced no new models in many years. In recent times, the website has been offline with monotonous, if unpredictable, frequency. While their paid-for models have all been permanently reduced in price now, this problematic access to the site (which also restricts you to a limited number of downloads for each item purchased) means that if any of their models do appeal, be sure to make plenty of backup copies of anything you buy and download from them.
As someone who's spent a lifetime making and designing paper and card models, my recommendation would be to check around for paper models and miniatures via the OneBookShelf sites (some manufacturers are not on both DTRPG and Wargame Vault, for instance), but perhaps more usefully, to also check-out, and spend some time looking through, the copious amounts of information freely available on the ProBoards Cardboard Warriors Forum. That Forum provides access to vast numbers of free minis and models (often via the One Monk Miniatures website), with links to many more stored elsewhere (including via the Internet Archive, for those items no longer on active websites), while many of the currently-active paper mini and model producers are often present there. You don't have to be a ProBoards member to access the Forum (free to join, and no real obligation beyond the usual Forum politeness, much as here), but if you want to post there, such as to ask questions (there's always someone happy to try to help, if possible), you will need a ProBoards account. You may even notice a curiously familiar moniker among the contributors there...
Just wanted to say too it was nice to see Dioramas 3 getting a little love via this Annual issue!