ERD Lab is an online ER Diagram Tool that allows you to visually design your database.
You can import existing SQL or create a new database without writing any code. Visualize your schemas and collaborate with your team. When you are done, export SQL or PDF/Image. All this for free
MySQL Workbench - MySQL Workbench is a unified visual tool for database architects, developers, and DBAs.
drawDB - Free, simple, and intuitive online database design tool and SQL generator.
Database diagram - Design ER diagrams by just typing code
HeidiSQL - HeidiSQL is a powerful and easy client for MySQL, MariaDB, Microsoft SQL Server and PostgreSQL. Open source and entirely free to use.
dbForge Studio for PostgreSQL - dbForge Studio for PostgreSQL is a universal GUI tool for PostgreSQL databases development and management with options to create and execute queries in the IDE.
Liam ERD - Automatically generates beautiful and easy-to-read ER diagrams from your database.