Electromagnetic exotics

Anyone have experience or done experiments with electrically conductive filaments, or magnetic filaments?

I've printed a little with ProtoPasta's conductive filament (30-115 Ohm resistivity), and it's pretty neat. (See: https://www.proto-pasta.com/pages/conductive-pla). Combined with dual extrusion I made some test prints to check its conductivity over various lengths and shapes. It definitely conducts well enough to light LEDs over short-ish distances at 5-9v, and can be used for capacitive touch with Arduinos, but it's definitely not suitable for high wattage applications. Not being a skilled electrical engineer, however, my imagination and technical skill probably aren't making full use of its potential.

I also just picked up some of ProtoPasta's iron/ferromagnetic filament, but haven't printed with that yet.

Combining the two, especially with dual extrusion, sounds promising for low power printed capacitors, inductors, antennas, sensors, etc., but again my technical skill there is a bit lacking. Clearly it can be used for push-button digital switches and other low-amp power applications. It would be interesting to use it to design fully-printed solid-state endstop switches for printers, eliminating (or at least pushing back) one more RepRap Vitamin. It's inherent resistance lends itself well to digital switches.

So does anyone have ideas/suggestions/experience dealing with these filaments, or things to try out? I currently have a three-color setup (soon to be four) that can be used to combine conductive, magnetic, and non-conductive filaments in the same print (within the limits of normal printing and tool change  tolerances).

I don't imagine that printed motors or generators would be too practical due to the high resistance and low permittivity of these materials, not to mention frictional losses between printed parts, but it seems like there's a lot of potential here for some additional types of sensors or switches.