Chain Generator, from Liryc Creative Design Studio, is a Blender add-on for creating CG metal chain parts that are difficult to produce manually or through photogrammetry. It includes 60 types of photorealistic chain parts and 16 high-quality materials incorporating fashion trends, with every part built at real-world scale.
The add-on runs on customizable geometry nodes, so you can generate as many chains as you want and adjust them without a fixed limit. You can also turn your own objects into chains. It renders through Cycles and Eevee and ships under a GPL license.
Chain Generator is a Windows-only add-on; Mac users are pointed to an equivalent asset with the same functionality on the developer's page. Commercial use is permitted when the asset forms part of a work or production, while redistributing or selling the raw asset data is not. The developer has released several specification updates and notes future free updates.