Avira Home Gaurd - Avira Home Guard is a free home network scanner app that helps secure the smart home, detects all devices connected to your Wi-Fi and tests your internet speed.

Multiping - Get MultiPing Support. Network monitoring in 60 seconds. MultiPing provides a graphical view of network performance, monitors hundreds of targets, and sends automatic alerts..

Angry IP Scanner - Open-source and cross-platform network scanner designed to be fast and simple to use

Fping (open source) - fping is a program to send ICMP echo probes to network hosts, similar to ping, but much better performing when pinging multiple hosts.

Nmap - Nmap Free Security Scanner, Port Scanner, & Network Exploration Tool. Download open source software for Linux, Windows, UNIX, FreeBSD, etc.

Ping Meter Gadget - Customizable, graphical, semi-transparent ping (latency) meter.