This is a parametric OpenSCAD script for generating two-dimensional springs. This is the same basic idea that many of the wobble arrestors and snap-in parts use: long, thin plastic segments that are designed to flex a bit. I just generalized the concept a bit.
These springs seem relatively sturdy, and they can be used along the XY plane, or (less ideally) along the Z axis.
You can make the springs stiffer and stronger by making them thicker (taller). Adjust the spring constant by changing the total length of the spring, either by adjusting the radii of the inner/outer circles, or by changing the arc angle of the springs.
Depending on the quality and calibration of your printer, you may or may not be able to make the springs thin enough that they turn into a single plastic filament. When I tried this, the springs were more flexible, but there were more errors in the print due to extruder starting/stopping and due to shrinkage. I made the springs two layers thick, and they print much more reliably now.