The following are design templates that can be used for specific types of Mozilla sites.
For sites that use the www.mozilla.org domain (compared to other sites using mozilla.org, such as air.mozilla.org) or are tightly integrated (such as Firefox product sites, such as SUMO and AMO) there is a standard header and footer template to use. The color and contents of the template can be updated based on the content (for instance, Firefox pages use a blue header, Mozilla pages use red, etc.)
Community Tools template
For community-facing sites that provide tools and infrastructure for the Mozilla project (Planet, phone book, wiki, etc.) there is a Mozilla-specific template that can be used.
Local community sites template
For community hosted sites for specific locales, there is the Mozilla Community Sites template.