Wiki: https://en.wikipedia.org/wiki/Data_integration Open
- OpenAddress
- OpenStreetMap
- OpenCorporates
- OpenSercets
- GeoNames
- OurAirports
- PpenFlights
- CorpWatc hhttp://api.corpwatch.org/
- DataOne
- Integrated Public Use Microdata Series (IPUMS): https://www.ipums.org/
Commercial
- Zillows
- CarFax