@mindcrime has put a pretty extensive list and explanation.
The things is, you are probably looking for a solution that does the reconciliation of data arriving from multiple sources and formats for you and preferably exposes it over an easy to use API.
The things is, you are probably looking for a solution that does the reconciliation of data arriving from multiple sources and formats for you and preferably exposes it over an easy to use API.
You can try http://unigraph.io, the API Sandbox (GraphQL) is available at: http://u01.unigraph.rocks and an extensive documentation covers it at: https://github.com/unigraph/docs/wiki
Currently Unigraph combines data from:
- wikidata
- geonames
- freebase
- crunchbase
- SEC EDGAR
- Companies House (UK).
A datadump is on its way and more sources will be added soon.
Disclaimer: I am building Unigraph, precisely for the reason of the question: "An open alternative to GKG".