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.
Fing - Discover which devices are connected to any Wi-Fi network, map devices, detect intruders, assess...
Ettercap - Ettercap is a suite for man in the middle attacks on LAN.
Nmap - Nmap Free Security Scanner, Port Scanner, & Network Exploration Tool. Download open source software for Linux, Windows, UNIX, FreeBSD, etc.
tcpdump - tcpdump is a common packet analyzer that runs under the command line.
SoftPerfect Network Scanner - Powerful multipurpose network administration tool for Windows and macOS