Wikibase is described as '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' and is an app in the Development category. There are six alternatives to Wikibase for Linux, Mac, Windows, Online / Web-based and Python. The best alternative is neo4j, which is both free and Open Source. Other great apps like Wikibase are RedisGraph (Free, Open Source), Structr (Free, Open Source), NetworkX (Free, Open Source) and LemonGraph (Free, Open Source).
RedisGraph is a 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.