Is there a market for broken parts?

I've performed open heart surgery on my beloved Nexus 4 today and changed its motherboard, because it randomly crashed when it ran on battery and the level reached a certain threshold. Also, I broke the battery connector when trying the cheap solution and putting a new battery in.

Now that I've successfully repaired my phone instead of just buying a new one, just as the Repair Manifesto tells us to, I wonder what to do with the old motherboard. All the motherboards you can buy for the Nexus 4 are used ones which probably already were refurbished, and my old one still has most of its parts working.

The question I'm asking myself now is: where do these used motherboards come from? Are there people that have a use for partially broken parts, who also might be able to fix them and reintroduce them into the repair cycle?