The Flexie Fidget is an awesome fidget toy that feels almost rope-like when played with. It is made up of 20 identical parts linked together. It prints fully assembled and only needs a little bit of gentle twisting to get all of the parts loose enough to rotate freely within each other. I have only tried to print this with PLA, but I don't see why other types of filament wouldn't work. 

Here is a video of a previous version (v2) of the Flexie Fidget. The current version (v4) is much improved and does not require you to peel off the bottom layer like in the video. 

NOTE: For best results, print with a layer height of 0.2mm or less.