SQL Developer - Oracle SQL Developer is a free, development environment that simplifies the management of Oracle Database in both traditional and Cloud deployments.
Adminer - Adminer (formerly phpMinAdmin) is a full-featured database management tool written in PHP.
phpMyAdmin - phpMyAdmin is a tool written in PHP intended to handle the administration of MySQL over the Web.
DBeaver - DBeaver - Universal Database Manager and SQL Client.
HeidiSQL - HeidiSQL is a powerful and easy client for MySQL, MariaDB, Microsoft SQL Server and PostgreSQL. Open source and entirely free to use.
DbVisualizer - DbVisualizer is the universal database tool for developers, DBAs and analysts.