I am not sure if any interesting ones have been made since focus shifted towards the 4 and 5. Maybe there are some specifically designed around using different HATs like UPS, LoRa, or the camera module.

I'm mostly seeing the average layered 3D printed cases and the mock consoles designed for emulation.

I'd also be interested in hearing some neat projects people are using them for. I have two spares from a while ago that I used for a NAS and an e-ink displayed weather forecast.