* RDFLib Store for PostgreSQL ( https://github.com/RDFLib/rdflib-sqlalchemy )

* Sparqlify is a SPARQL-SQL rewriter that enables one to define RDF views on relational databases and query them with SPARQL. ( PostgreSQL supported http://aksw.org/Projects/Sparqlify.html )

* PostgreSQL-Neo4j Foreign Data Wrappers https://github.com/nuko-yokohama/neo4j_fdw

* PgRouting (network ) http://docs.pgrouting.org/dev/doc/src/tutorial/analytics.htm...