ufw - Ufw stands for Uncomplicated Firewall, and is program for managing a netfilter firewall.
TinyWall - Lightweight and non-intrusive firewall
Windows 10 Firewall Control - Windows 10 Firewall Control: simple and exhaustive solution for applications network activity controlling and monitoring.
Gufw - Gufw is an easy, intuitive way to manage your Linux firewall.
Emsisoft Online Armor Firewall - Emsisoft Online Armor Firewall is a freemium online firewall protection system by the Emsisoft that is based on the own independent protection technology of the Emsisoft.
GlassWire - Visualize network activity in detail, get notified when new apps access the network, look out for...