What would you like to be added?

As per our ROADMAP, adding support for Graph Database Storage Layer. I think Nebula would be good fit for a graph Database (Also it is a CNCF Database Landscape Project)

https://github.com/clusterpedia-io/sample-storage, a sample of storage plugin , which might be helpful

Why is this needed?

The core point of supporting graph databases is to sort out the relationships between resources.