DBeaver - DBeaver - Universal Database Manager and SQL Client.
IBExpert - IBExpert website
MySQL Workbench - MySQL Workbench is a unified visual tool for database architects, developers, and DBAs.
Navicat - Powerful database management & design tool for Win, Mac & Linux. With intuitive GUI, user manages MySQL, MariaDB, SQL Server, SQLite, Oracle & PostgreSQL DB easily.
Firebird Maestro - SQL Maestro Group vendors powerful database management and web development tools for MySQL, Oracle, SQL Server, DB2, SQL Anywhere, PostgreSQL, SQLite, Firebird and MaxDB.
HeidiSQL - HeidiSQL is a powerful and easy client for MySQL, MariaDB, Microsoft SQL Server and PostgreSQL. Open source and entirely free to use.