Supabase - An open source Firebase alternative
Datahike - A durable datalog database adaptable for distribution.
SQL playground - Create a private PostgreSQL database with a predefined structure & test data in the shortest time.
Datomic - The fully transactional, cloud-ready, distributed database
Google Cloud PostgreSQL - Fully-managed database service
PlanetScale - The last database you'll ever need. Go from idea to IPO.