H3o is an awesome piece of work. I created polars bindings for it(another reason I love polars) and last time I benchmarked it, it had 5X better performance than even duckdb’s C++ implementation.

https://github.com/Filimoa/polars-h3

I really want to do a DuckDB extension someday, I think it would be pretty cool. I had looked into it 2 years ago but didn't dig further.

Now that H3 provides one, maybe I should take another look at it.