These are mostly SQL databases of various forms, usually RDBMS or MPP, but some without referential integrity or ACID compliance.
- DB Rankings
- Open Source Databases
- Cloud Databases
- Proprietary / Legacy Databases
- Databases Scaling Cheatsheet
- Database Sharding
https://db-engines.com/en/ranking
- MySQL - easy to use with easy DB replication features
- PostgreSQL - high quality open source database - the natural open source choice to move away from Oracle (one company where I was a semi Oracle DBA for a few years did exactly this migration after my time)
These are so popular that every major cloud provider has a managed service to host them for you - eg. AWS RDS, GCP Cloud SQL, Azure Databases and Digital Ocean Managed Databases.
Useful for local or embedded usage rather than multi-user servers like most major RDBMS systems.
- SQLite - small fast local SQL DB that can store data in a simple file .sqliterc config is available in the DevOps-Bash-tools repo
- DuckDB - single process local SQL DB akin to SQLite with minimal dependencies
- AWS Redshift - managed SQL cluster, built on ParAccel MPP columnar DB built on PostgreSQL, charges on a VMs running basis
- AWS Athena - serverless DB that operates on AWS S3 files or various data formats and charges by query
- GCP BigQuery - serverless DB that charges by query
- Oracle - an OG of RDBMS databases with good performance, durability and PL/SQL advanced SQL dialect. Notoriously expensive
- Microsoft SQL Server - slightly more user friendly than Oracle, with Transact SQL aka TSQL
- Netezza - specialist rack appliance, even more expensive than Oracle
