I started a little project in which I take iptables or pf tutorials and examples and try to reproduce rules found in them with fwbuilder. I put them in separate Firewall Builder Cook Book chapters. Right now I have few chapters about different ways to configure the firewall for transparent proxy and well as some other things. It isn't much but I intend to keep adding more examples as I find them.
I try to follow the same format in these chapters, where I provide a link to the original document, then add screenshots to demonstrate how this can be done in fwbuilder and then provide snapshots of generated rules as well as a copy of the rules from the original document for comparison.
Some examples are rather trivial, while others are not. See the chapter about iptables setup for IPP2P module. Regardless of whether you need to do anything with P2P traffic and therefore need the module or not, this chapter demonstrates interesting mangle rules and how they can be done in fwbuilder. This can be useful in other situations, not only for the IPP2P module.
Please send pointers to the examples you'd like me to add to the Cook Book. Anything goes, but rules in your examples should be relatively complex and not covered by existing chapters. If you have some interesting example of your own, not found in some tutorial on the web, please send those as well.
Firewall Builder CookBook can be found here