DBeaver - Universal Database Manager and SQL Client. DBeaver is free and open source universal database tool for developers and database administrators.
HeidiSQL is a useful tool designed for web developers using the popular MySQL server, Microsoft SQL databases and PostgreSQL. It enables you to browse and edit data, create and edit tables, views, procedures, triggers and scheduled events.
MySQL Workbench is a unified visual tool for database architects, developers, and DBAs. MySQL Workbench provides data modeling, SQL development, and comprehensive administration tools for server configuration, user administration, and much more.
phpMyAdmin is a tool written in PHP intended to handle the administration of MySQL over the Web. Currently it can create and drop databases, create/drop/alter tables, delete/edit/add fields, execute any SQL statement, manage keys on fields.
pgAdmin is the most popular and feature rich open source administration and development platform for PostgreSQL, the most advanced open source database in the world.
Open Source SQL Editor and Database Manager for MySQL, SQL Server, Postgres, Redshift, Sqlite and more.
Sequel Pro is a fast, easy-to-use Mac database management application for working with MySQL databases.
No releases since 2016. Difficulty with newer OSes cause the app to crash when closing a connection.
SQuirreL SQL is an open-source Java SQL Client program that will allow you to view the structure of a JDBC compliant database, browse the data in tables, issue SQL commands etc.