I have some drag chain for my laser cutter, and the length I had was too short. Rather than order another meter and wait for it to take a slow boat from China, I re-created the design in OpenSCAD and printed a dozen links. 1 hour to design, 4 to print.
The chain I started with was purchased here: https://www.banggood.com/10-x-10mm-Plastic-Cable-Drag-Chain-Wire-Carrier-Length-1000mm-With-End-Connectors-For-CNC-p-995511.html
I printed in PLA, 0.3mm layer height with 20% infill, full support. In Prusa Slicer, this is "draft", but it's totally adequate for my purposes. The little tab that limits how far the chain can bend needs to be modified a bit, since it won't allow the chain to lie flat. For me, it was faster to just take the links to a belt sander and remove about 1mm than to fix the model and reprint. A fixed but untested version of the model is in link_fixed.scad for the adventurous.