RedisGraph is described as 'property graph database module for Redis. It is the first graph database to use linear algebra on sparse adjacency matrices to implement graph operations, which lets it achieve high performance. It understands OpenCypher queries'. There are more than 10 alternatives to RedisGraph for a variety of platforms, including Linux, Mac, Windows, Online / Web-based and BSD. The best alternative is Wikibase, which is both free and Open Source. Other great apps like RedisGraph are ArangoDB (Free, Open Source), neo4j (Free, Open Source), GraphStack.io (Free, Open Source) and Bitsy graph database (Free, Open Source).
Wikibase is the software that runs Wikidata, but is also usable for other projects beyond that. Wikibase allows the collaborative editing of structured data on top of MediaWiki. It is optimized for graph-like, schema-poor data, not for tabular and strongly pre-structured data.