Neofetch - Fancier version of Screenfetch that displays colors and supports more platforms.
Fing - Discover which devices are connected to any Wi-Fi network, map devices, detect intruders, assess...
Archey 4 - Archey 4 is a system information tool written in Python
Nmap - Nmap Free Security Scanner, Port Scanner, & Network Exploration Tool. Download open source software for Linux, Windows, UNIX, FreeBSD, etc.
Speccy - Speccy - find the details of your computer's specs. Great for spotting issues or finding compatible upgrades. Download the latest version free.
SoftPerfect Network Scanner - Powerful multipurpose network administration tool for Windows and macOS