Yabb Message Forum
The most comprehensive CGI message board I've ever seen. Did I mention it's free? This is definitely a must try. The graphics and functionality of YaBB are gorgeous.

Form Mail
Free form to email script. Your visitors fill in a form on your website and the results are emailed to you.

Active Guestbook
Active Guestbook is fast becoming the guestbook of first choice on the web. Now used on thousands of sites around the world, easy to install, and free for non-commercial use.

Free CGI Shopping Cart
Commerce.cgi is a full shopping cart system complete with a browser based store manager for adding, editing, and deleting products from your inventory. Pages are dynamically created from a flat file database. It also includes support for a wide selection of online credit card processors, or you can choose offline order processing.

Ringlink
A free Perl program that provides the tools you need to run one or more webrings, i.e. systems of links between related web sites.

Jason's Postcards
This free postcard cgi script allows visitors to send Postcards to a friend, while increasing your exposure on the web.

KSearch
A fast, efficient, and highly customizable web site indexer and search engine. A perfect addition to any web site, large or small.

CopThis
Free refer a friend cgi script so your visitors can refer your website to their friends. Great for website promotion.