📝Resource Description Framework (RDF)
RDF databases
TerminusDB / terminus-store—based on RDF, though use custom store/query APIs. Also support “git-like branching and merging.” Written in Rust.
Oxigraph—an RDF datastore written in Rust. Supports SPARQL and RDF*
Datomic / DataScript are triplestores, though entities/attributes don't have to be IRIs. Datomic also supports transactions and historical queries.