OpenSnitch is described as 'GNU/Linux application firewall' and is a Firewall in the security & privacy category. There are more than 25 alternatives to OpenSnitch for a variety of platforms, including Linux, Windows, Mac, Android and iPhone apps. The best OpenSnitch alternative is Portmaster, which is both free and Open Source. Other great apps like OpenSnitch are simplewall, Pi-hole, GlassWire and Fort Firewall.
Bouncer is an application to help you choose the correct firewall zone for wireless connections. When you connect to a new network, Bouncer will open a window prompting you for what kind of network (eg home, public, work) it is.
DataCever allows you to monitor and control internet traffic , allowing you to know what consumes your data plan.
