AFT (Almost Free Text) is a document preparation system. It is mostly free form, meaning that there is little intrusive markup; AFT source documents look a lot like plain old ASCII text. It has a few rules for structuring your document, more to do with formatting your text than embedding lots of commands, and it produces all types of output (HTML, XHTML, LaTeX, roll-your-own XML, etc.). All that needs to be done is to edit a rule file. You can even customize your own rule files for specialized output.
FAQ PLAIN is a simple FAQ preprocessor. It generates a single FAQ output page which can be used for HTML PLAIN, or as an include page. It offers a some very useful options such as a hierarchical structure of the FAQ with automatic numbering. The program is easy to use and greatly simplifies the task of creating an FAQ page.
filepp is a generic file preprocessor designed to allow the functionality provided by the C preprocessor to be used with any file type. It supports the full set of C preprocessor keywords (#include, #define, #if, etc.). filepp is also highly customisable and allows users to easily add their own keywords or modify the behaviour of existing keywords.
The Guava tools are a set of Perl scripts for HTML pre-processing. You can create multi-page documents with contents tables, or use templates to give a consistent look to a set of pages. All output is passed through the C preprocessor, so you can use directives such as #include, #define and #if. There are also built-in macros for producing dates, cross references, etc.
HTML::Mason is a full-featured web site development and delivery system. Mason allows web pages and sites to be constructed from shared, reusable building blocks called components. Components contain a mix of Perl and HTML, and can call each other and pass values back and forth like subroutines. Components increase modularity and eliminate repetitive work. HTML::Mason is most powerful when used in conjunction with mod_perl, but can be used in standalone applications as well.