Zabbix - Track, record, alert and visualize performance and availability of IT resources
inSSIDer - inSSIDer Essential makes it easy to maintain small business WiFi.
Datadog - See metrics from all of your apps, tools & services in one place with Datadog's cloud monitoring as a service solution. Try it for free.
NetStumbler - Official source of information about Netstumbler.
Wireshark - Wireshark is a network protocol analyzer for Unix and Windows. It lets you capture and interactively browse the traffic running on a computer network.
NetSpot - NetSpot is a free app for wireless site surveys, Wi-Fi analysis, and troubleshooting