๐Resource Description Framework (RDF)
RDF databases
TerminusDB / terminus-storeโbased on RDF, though use custom store/query APIs. Also support โgit-like branching and merging.โ Written in Rust.
Oxigraphโan RDF datastore written in Rust. Supports SPARQL and RDF*
belayeng/quadstoreโan RDF datastore written in JS
Datomic / DataScript are triplestores, though entities/attributes donโt have to be IRIs. Datomic also supports transactions and historical queries.