RumbleDB is a fairly new system that provides for JSON data what XQuery provides for XML data. That is a way to query the data with an sql-like syntax, and to do it efficiently on very large scale data (as well as for small-scale data). I have not actually worked with it yet but it looks like brilliant work.
The feature that caught my attention regarding Leo is that they have a capability for interfacing with Jupyter Notebook via a server they launch. It would seem that the Leo bridge, maybe in combination with leo-server, ought to be able to do that job: make it possible for Leo to interface with Rumble without having to launch command line programs for each command. It might be something that I could integrate with VR3 at some point.
I don't know if the Bridge would need some enhancement for this purpose or not. I'm too engaged with a current project to spend time on this right now. Maybe someone else will have an interest.