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.
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.
DataGrip is a database IDE from JetBrains that is tailored to suit specific needs of professional SQL developers.
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.
Adminer (formerly phpMinAdmin) is a full-featured database management tool written in PHP. Conversely to phpMyAdmin, it consist of a single file ready to deploy to the target server. Adminer is available for MySQL, PostgreSQL, SQLite, MS SQL and Oracle
Navicat is a database administration tool that allows you to simultaneously connect to MySQL, MariaDB, SQL Server, Oracle, PostgreSQL, and SQLite databases from a single application.
DbGate is cross-platform database manager. Simple and effective, allowing to work with many various databases simultaneously - SQL and NoSQL.
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.