DaFT is a frontend to any database that can be connected via ODBC. It provides list views of tables and columns, table view of data, SQL editor, CSV,HTML,SyLK,XLS data format export, and functions for copying data between two ODBC databases.
sqsh2 is a database independent sql client for terminal environment of Unix/Linux (~isql) with 1) command history 2) command editing via vi 3) shell integration 4) multiple db connections. sqsh2 is inspired by sqsh (Thank you Scott).
DB Copy Plugin is a plugin for the SQuirreL SQL Client (1.2beta6 and 2.0 RC1+) that allows copying database objects (schema def and data) from one session window to another. The sessions can be disparate database vendors (Oracle -> MySQL, for instance).
...Connects to any JDBC compliant database and will run on any OS with a Java VM. Features: keyword highlighting, result formatting, statement history, multi-window, multiple database connects at one time.