This gives you MongoDB and PostgreSQL coverage in one place, which is honestly pretty practical since most projects end up touching both at some point. It includes the usual CRUD operations, indexing strategies, and aggregation pipelines for Mongo, plus SQL queries, psql commands, and performance tuning for Postgres. The selection guide up front is helpful for choosing between document and relational models. It also throws in Python scripts for migrations, backups, and performance checks. The side-by-side examples make it easy to translate concepts between the two systems when you're context switching.
npx skills add https://github.com/mrgoonie/claudekit-skills --skill databases