Glom is a GUI that allows you to design MySQL table definitions and the relationships between them. It also allows you to edit and search the data in those tables.
The PHP Accelerator is an easily installed PHP Zend engine extension that provides a PHP cache, and is capable of delivering a substantial acceleration of PHP scripts without requiring any script changes, loss of dynamic content, or other application compromises.
SafeSQL is an SQL query processer to automate the tedious tasks of syntax testing, injection attack-proofing, dropping parts of queries and other misc features.
Postgresql AutoDoc is a utility which will run through PostgreSQL system tables and returns HTML, DOT, and 2 styles of XML which describes the database.
mysqldiff is a Perl script which compares the data structures (i.e. table definitions) of two MySQL databases and returns the differences as a sequence of MySQL commands suitable for piping into mysql which will transform the structure of the first database to be identical to that of the second.