Alfandega is a strong and Modular IpTables Firewall. It provides NAT, port-forwarding, spoofing list, blacklist of crackers and spywares sites, protection for tcp/udp scans, DOS/DDOS and Smurf attacks, TCP tuning, DHCP and PPP support and much more.
DaemonWall is an OpenBSD-based network security live CD which can act as an Internet firewall/gateway.
FireGate is an IPtables script for use as a firewall and NAT/masquerade for home networks or SOHO applications.
Easy to use firewall configuration script, featuring statefull connection tracking, bandwidth limiting and bandwidth logging.
The SunGazer PacketFilter is a small and simple tool under GPL to set up firewall rules. It uses iptables and it is easy to use and to configure.