I've spent the past ~year compiling a US nationwide land parcel dataset. I posted it to kaggle a few days ago: https://www.kaggle.com/datasets/landrecordsus/us-parcel-laye....
I'm around 99% coverage of the US. Learned a lot about land records and GIS along the way.
This is really cool. What do you think the remaining ~1% is?
Could be interesting for finding winners and losers of a potential land value tax