• SQLMinus (has an "auto-link" feature)
• SQLWorkbench
  • auto-query neighboring tables based on foreign key relationships
  • command completion on tables/fields
    (oh, only fields?)
  • macros, with variable substitution, AND the ability to prompt for unset variables
  • reformat SQL statements
  • copy data between databases
• [Java] SQuirreL SQL (syntax hilighting, code completion)
• [Java] iSQL Viewer (syntax hilighting, bookmarks)
• DBBrowser