Nmap - Nmap Free Security Scanner, Port Scanner, & Network Exploration Tool. Download open source software for Linux, Windows, UNIX, FreeBSD, etc.
Kon-Boot - Kon-Boot is a password hacking, password recovery tool for Windows and Mac.
Fing - Discover which devices are connected to any Wi-Fi network, map devices, detect intruders, assess...
ophcrack - Ophcrack is a Windows Password cracker based on Rainbow Tables. Features
Advanced IP Scanner - Advanced IP Scanner shows all network devices, gives you access to shared folders, and can even remotely switch computers off. Download it Free.
hashcat - The World's Fastest CPU/GPU powered password cracker.