CGIWrap is a setuid wrapper that allows users to install and execute their own cgi scripts that get executed as their own userid. Much of the idea of suexec came from CGIWrap, however, cgiwrap stands on its own, and works with all web servers. CGIWrap must be installed by a system administrator, but after that, users can do their own web scripting.
Ilib is an image manipulation library for developers. It's capable of reading and writing images (PPM/PGM, PNG, JPEG, GIF, XPM, BMP) and many drawing functions including drawing lines and text using any BDF (X11) font. It's great for generating GIFs/PNGs from a CGI or generating graphs. Ilib includes sample applications for generating graphs for HTTP access.log files and QuakeWorld server frag log files and a tool for creating image indices from a group of images.
WPP is a small perl5 script that allows preprocessing of HTML files. It allows you to define "variables", which are brief abbreviations for longer constructs, and include common HTML fragments. It's useful for giving a uniform layout to different HTML pages. It can be used in cgi-bin programs for automatic generation of pages. With less HTML code inside you can make more flexible cgi-scripts.