Total Network Inventory: Professional PC audit and network inventory management software - fits best for a for companies of all sizes. Free for 60 days.
ManageEngine Desktop Central - Desktop Central is a Desktop Management and Mobile Device Management Software for managing desktops in LAN and across WAN and mobile devices from a central location. It supports managing Windows, Mac and Mobile devices running iOS 4 and above
Network Inventory Advisor - Network Inventory Advisor audits all network software and hardware simply and efficiently
Freshservice - Freshservice: the one-stop cloud solution for all your IT management needs.
Lansweeper - Lansweeper discovers Windows, Linux and Mac machines in your network.
Ivanti Unified Endpoint Manager - Consolidate & supercharge your endpoint security with desktop management software from Ivanti. Discover how to gain greater visibility into your devices while boosting productivity with Ivanti Unified Endpoint Manager.
Nmap - Nmap Free Security Scanner, Port Scanner, & Network Exploration Tool. Download open source software for Linux, Windows, UNIX, FreeBSD, etc.