Synthesizers (and related stuff, such as effects or virtual instruments) qualify too. I don't know if there are other instruments which trigger this behavior.
I was aware of photography. But it's remarkable that guitars and synths seem to be the only two instruments.
> It's linked to the dopamine anticipation loop that buying an item feels like you're making progress.
I'm not fond of such explanations. The brain is so much more than dopamine. I don't think there's even a thorough explanation linking buying a guitar and dopamine, let alone one that can link it purely to dopamine. Buying is not a loop either.