My project hasn't really gotten to the level of actually exporting data to any database yet, but basically I'm just using standard openstreetmap data exported to geoparquet format.

That is then combined with a bunch of time series sensor readings combined with a gps data, (I'm basically still working on the device firmware so I don't have any actual data export happening yet)...

But it is a pretty basic combination of timeseries and geospatial data.