gd is a library for creating and reading PNG, JPEG, GIF, WBMP, and XPM images. It has many features and can be used in scripts (e.g. PHP, Perl, Ruby, Lua, and Python) for dynamic image generation. PHP users should note that PHP 4.3.x includes its own distribution of gd, which is currently the best choice for PHP applications.
The Zip extension for PHP aims to provide a convenient and powerful set of functionality to work with zip archives. It can read, write, and create zip archives. It also supports stream access to any archive entry. It is 100% compatible with the old versions of the extension (which were read-only).
The Enchant extension aims to provide a full featured Enchant binder for PHP. The Enchant library provides a common API to work with many spelling tools. All inputs and outputs are in UTF-8 encoding. All language tags are based on ISO standards. It supports: Aspell/Pspell (intends to replace Ispell), Ispell, MySpell/Hunspell (an OOo projects also used by Mozilla), Uspell (primarily Yiddish, Hebrew, and Eastern European languages), Hspell (Hebrew), and AppleSpell (Mac OS X).
PEAR HTML_Template_IT provides two APIs to work with templates, a simple template API and an extended version. It supports blocks (including nested blocks), external file inclusion, and a custom tags format. With ITX, it is possible to modify blocks, replace or add blocks from files, and use callback functions.
PEAR Validate is a set of useful methods to validate various kinds of data. It supports numbers (min/max, decimal, or not), email addresses (syntax, domain check, RFC 822), strings (alpha, upper and/or lowercase, numeric), dates (min, max), URIs (RFC 2396), and more. It also has many locale validation rules, specialized for each country or region (US, FR, UK, DE) or application domain (such as finance).