DBeaver is a free multi-platform database tool for developers, SQL programmers, database administrators, and analysts.

DBeaver supports all popular databases: MySQL, PostgreSQL, MariaDB, SQLite, Oracle, DB2, SQL Server, Sybase, MS Access, Teradata, Firebird, Derby, etc.

DBeaver features:

Usability is the main goal of this project, program UI is carefully designed and implemented.
It is free and open-source (ASL).
It is multiplatform.
It is based on the Open Source framework and allows writing of various extensions (plugins).
It supports any database having a JDBC driver.
It may handle any external data source which may or may not have a JDBC driver.
There is a set of plugins for certain databases (MySQL, Oracle, DB2, SQL Server, PostgreSQL, Vertica, Informix, MongoDB, Cassandra, Redis in version 3.x) and different database management utilities (e.g. ERD).
It has a great number of features.