Well now, here is the great strength of working digitally I suppose as you can try out different backgrounds on their own separate layer to see what looks best!
I would suggest something not too “busy” so as not to compete for the viewer’s attention. And maybe with a gradient so that it’s not just flat, mimicking the light direction on the sculpture.
Imagine you were setting this up as a photo shoot in a studio where you have complete control of the backdrop and lighting.