DBeaver - DBeaver - Universal Database Manager and SQL Client.
DataGrip - Tool for SQL and databases
IBExpert - IBExpert website
HeidiSQL - HeidiSQL is a powerful and easy client for MySQL, MariaDB, Microsoft SQL Server and PostgreSQL. Open source and entirely free to use.
FlameRobin - FlameRobin is a cross-platform, open-source database administration tool for Firebird DBMS.
Navicat - Powerful database management & design tool for Win, Mac & Linux. With intuitive GUI, user manages MySQL, MariaDB, SQL Server, SQLite, Oracle & PostgreSQL DB easily.