Google Cloud PostgreSQL - Fully-managed database service
Supabase - An open source Firebase alternative
Hasura - Hasura is an open platform to build scalable app backends, offering a built-in database, search, user-management and more.
Slack SQL - Execute SQL queries inside of Slack
Crunchy Bridge - Crunchy Bridge is a fully managed database as a service.
Firebase - Firebase is a cloud service designed to power real-time, collaborative applications for mobile and web.