The Bridge Public Records API allows users to retrieve parcel, assessment and transactional county data across the entire US going back roughly 15 years. The...
In terms of aggregate data at the neighborhood level, can be found here – https://www.zillow.com/research/data/ They are freely available for download via CSV.
The Zillow Economic Research team publishes a variety of real estate metrics including median home values and rents, inventory, sale prices and volumes, negative equity,...