DBeaver - DBeaver - Universal Database Manager and SQL Client.
FlameRobin - FlameRobin is a cross-platform, open-source database administration tool for Firebird DBMS.
RazorSQL - RazorSQL is an SQL Editor and SQL database query tool for macOS, Windows, Linux, and Mac OS X.
DbGate - Open Source Database Manager for SQL Server, MySQL, PostgreSQL, SQLite, MongoDB, Redis and more
Aqua Data Studio - Aqua Data Studio is productivity software for Database Developers, DBAs, and Analysts.
SQLTools - SQLTools is a light weighted and robust tool for ORACLE database development.