TinyWall - Lightweight and non-intrusive firewall
Barracuda Web Application Firewall - Barracuda Web Application Firewall offers security and DDoS protection against automated & targeted attacks.
SonicWall - SonicWall security solutions protects your network, systems, users and data from cyber threats.
AWS WAF - AWS WAF is a web application firewall that helps protect your web applications from common web exploits.
pfSense - pfSense is a free and open source firewall and router that also features unified threat management, load balancing, multi WAN, and more
ModSecurity - ModSecurity is an Open Source web application firewall developed by Trustwave's SpiderLabs.