Wolf Software MySQL Class is a lightweight but comprehensive PHP class for accessing MySQL databases in a simplistic way. It has built-in error handling, simplifies the use of MySQL, and escapes special characters. It can be used with simple or persistent connections and can be integrated easily into any PHP Web project.
Vault is a PHP class for implementing security and encryption. It was designed and built for use in the Vault product range (Message Vault and Password Vault), but has been released in its own right for others to benefit from. It uses a combination of symmetric and asymmetric encryption including SSL (2048), SHA256, SHA512, and ASE256. It also features randomly generated salts and key verification.
The PHP Messages class is a simple, lightweight PHP class for handling default user based messages. It has a small selection of extensible functions for warnings, errors, etc. It is very customizable, allowing for flexibility while allowing consistent looking messages to be displayed.
Page Security is a small PHP class which attempts to close a couple of the security holes within default PHP configurations. Currently it will allow you to turn off all error reporting, undo gc_magic_quotes, apply a basic whitelist or blacklist to a page, and also verify the HTTP context by which a page has been called. Most of these should be considered "best practices" rather than major security vulnerabilities.