Ping Meter Gadget - Customizable, graphical, semi-transparent ping (latency) meter.
Nmap - Nmap Free Security Scanner, Port Scanner, & Network Exploration Tool. Download open source software for Linux, Windows, UNIX, FreeBSD, etc.
SmokePing - Smokeping is a tool for measuring latency.
MiTec Network Scanner - A free multi-threaded ICMP, Port, IP, NetBIOS, ActiveDirectory and SNMP scanner with many advanced features.
Open Nettest - Open Nettest is a platform for collecting, processing and visualizing data related QoS and QoE.
Fingbox - Fingbox home network security device helps you keep your internet safe and secure, allows you to monitor your household digitally and improve your home Wi-Fi experience.