Papercraft is the art of making models using only paper, wether it be heavy stock paper, cardboard, or normal notebook paper. Papercrafting has been around for a long time now, but I can imagine Gundam papercraft starting when one fan wanted a model for a Gundam that wasn’t on the market yet. That is the true power of Gundam papercraft, the ability to make any mobile suit you want, and make it to any proportion (ie. chibi Gundams).
But most do not make their Gundam’s from scratch. Instead they use pre-made templets, and use those blueprints in order to help construct the Gundam. However, these templets are hard to come by, but if you really scour the internets you can find them. Anyways, check out this amazing gallery of Gundam papercraft, and remember, all of these are created only using paper!