WML is a free and extensible Webdesigner's off-line HTML generation toolkit for Unix, distributed under the GNU General Public License (GPL v2). It is written in ANSI C and Perl 5.
TinyButStrong is a library that enables you to create HTML pages dynamically. It's a template fngine for the PHP language. It enables you to easily display information from your database, but also to seriously harmonize and simplify your PHP code.
Savant is a powerful but lightweight object-oriented template system for PHP. Savant by default does not compile your templates into PHP, instead it uses PHP itself as its template language so you don't need to learn a new markup system. LGPL
Smarty provides the programmer and template designer with a wealth of tools to automate tasks commonly dealt with at the presentation layer of an application.
phpDocumentor creates professional documentation from php source code. phpDocumentor has support for linking between documentation, incorporating user level documents like tutorials and creation of highlighted source code.
ClearSilver is a fast, powerful, and language-neutral template system. It is designed to make it easy to create template driven static or dynamic websites. Modules currently available for C, Python, Perl.