This is a fun little fidget toy built using a two dimensions chain link that I designed based on a toy my children had years ago. (Two dimensional in this case means that the chain can bend in two directions instead of just one.) The chain ring can bend in many surprising ways, and can even be rotated about its center so that it becomes "inside out".

Easy to print without supports although if you scale it up things can start to droop between some of the links.

You can also take the link and combine them by rotating them 90 degrees about their long axis and lining up the cones and the pits on another link (1.5 cm centers). In that way, you can make chains as long as you would like.

Depending on your printer you may need to gently separate the overlapping tangs on the corner pieces. But on my printer, separation was very minor and they just snapped apart making the entire chain bendable and rotatable nearly straight off the printer with no cleanup.