Unbounded - Serverless NoSQL database you query with JavaScript
Datomic - The fully transactional, cloud-ready, distributed database
pREST - A fully RESTful API from any existing PostgreSQL database written in Go
Google Cloud Datastore - Cloud Datastore is a NoSQL database for your web and mobile applications.
Supabase - An open source Firebase alternative
Datahike - A durable datalog database adaptable for distribution.