pfSense - pfSense is a free and open source firewall and router that also features unified threat management, load balancing, multi WAN, and more
StackPath - Secure Content Delivery Network, DDoS, WAF Service
OPNsense - OPNsense® you next open source firewall. Free Download. High-end Security Made Easy™. Offers Intrusion Prevention, Captive Portal, Traffic Shaping and more.
Avast - Avast security software products are developed for Microsoft Windows, Mac OS X, Android and Linux users by AVAST Software.
IPFire - IPFire is a server distribution with intended to use as a firewall.
Flexera Software Vulnerability Manager - Flexera Software Vulnerability Manager provides solutions to continuously track, identify and remediate vulnerable applications.