Popular Web Application Firewall (WAF) solution providers include the below list
ModSecurity: An open-source WAF module that can be integrated with web servers like Apache and Nginx. It provides customizable rule sets to detect and prevent various types of web application attacks.
Imperva WAF: A commercial WAF solution that offers advanced threat protection, application security, and bot mitigation. It provides real-time attack detection and automatic updates to stay up-to-date with emerging threats. They provide both solutions in the cloud and on-prem setup.
Akamai Web Application Protector: This cloud-based WAF by Akamai offers scalable protection for web applications against various types of attacks, including DDoS attacks, SQL injection, and more.
Cloudflare WAF: Cloudflare's WAF is part of its broader security suite and offers protection against OWASP top 10 threats, DDoS attacks, and other malicious activities. It is available both for individual websites and enterprise-level applications.
Radware: Radware WAF delivers solutions for physical, cloud and software defined data centers. It also include BOT and DDOS mitigations. They also protection solutions for client-side to mitigate supply-chain events.
F5 BIG-IP Application Security Manager (ASM): F5's ASM is a comprehensive application security solution that includes a powerful WAF to protect against various application-layer attacks and vulnerabilities.
Barracuda Web Application Firewall: A hardware or virtual appliance WAF that provides protection against threats like SQL injection, cross-site scripting, and more. It also offers bot mitigation and secure application delivery.
Wallarm: Wallarm's WAF combines security automation with machine learning to provide real-time application protection against attacks. It's designed to work in modern application environments, including microservices and APIs.
AWS WAF: Amazon Web Services (AWS) offers a cloud-based WAF that can be integrated with AWS services or deployed on-premises. It helps protect web applications from common web exploits and vulnerabilities.
These are just a few examples, and there are many other WAF solutions available with varying features, deployment options, and levels of customization. When selecting a WAF, organizations should consider factors such as the specific threats they want to defend against, the ease of integration, performance impact, scalability, and management capabilities.
The above list is just an example and it's possible that things have changed since. Also every organization has different needs, so please evaluate based on your requirement and level of risk that needs to be protected.