ModSecurity - ModSecurity is an Open Source web application firewall developed by Trustwave's SpiderLabs.
Imperva SecureSphere - Get the flexibility, reliability, and performance you need to protect your business. SecureSphere covers you both on-premises or in the cloud.
Naxsi - NAXSI means Nginx Anti XSS & SQL Injection.
Shadow Daemon - Shadow Daemon is a collection of tools to detect, record and prevent attacks on web applications.
F5 NGINX - F5 NGINX is a web application security solution that allows you to protect your applications, APIs, and customer data across cloud servers, on-premises data centers, and architectures.
AWS WAF - AWS WAF is a web application firewall that helps protect your web applications from common web exploits.