SQLite, LMDB and RocksDB are all popular and embedded. They're not really web-centric though so don't get as much exposure on HN and its ilk. Edit: Sorry if I

SQLite, LMDB and RocksDB are all popular and embedded. They're not really web-centric though so don't get as much exposure on HN and its ilk. Edit: Sorry if I sound like "that guy," just offering up some names in case people aren't familiar with them.