Jupyter - Project Jupyter exists to develop open-source software, open-standards, and services for interactive computing across dozens of programming languages. Ready to get started? Try it in your browser Install the Notebook.
DBeaver - DBeaver - Universal Database Manager and SQL Client.
Boostnote - Boostnote is an open-source note-taking app.
DataGrip - Tool for SQL and databases
iPython - iPython provides a rich toolkit to help you make the most out of using Python interactively.
HeidiSQL - HeidiSQL is a powerful and easy client for MySQL, MariaDB, Microsoft SQL Server and PostgreSQL. Open source and entirely free to use.