Oracle SQL Developer is a free and fully supported graphical tool for database development. The catch is that users must have/create an Oracle account to be able to download it. It is Java based and the path to Java on the workstation will need to be configured in SQL Developer for it run properly after install.
With SQL Developer, you can browse database objects, run SQL statements and SQL scripts, and edit and debug PL/SQL statements. You can also run any number of provided reports, as well as create and save your own. SQL Developer enhances productivity and simplifies your database development tasks. You can download the installer here.