Apache Age: A Graph Extension for PostgreSQL
Though i appreciate all the hard work people put into this and offer it so generously for free, it kind of saddens me to see yet another property graph database that supports some non-standardized (not really anyway) query language. I would really like to see a free and rdf based triple-store with good SPARQL support and that can be used for serious production workloads. But all the open source activity seems to be in the property-graph camp, with a new product every couple of month, while the high-quality triple stores are all quite pricy.