MySQL - The world's most popular open source database
IBExpert - IBExpert website
PostgreSQL - PostgreSQL is a powerful, open source object-relational database system.
DBeaver - DBeaver - Universal Database Manager and SQL Client.
SQLite - SQLite Home Page
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.