NetBox - NetBox is an open source web application designed to help manage and document computer networks. NetBox was developed specifically to address the needs of network and infrastructure engineers.
ManageEngine OpUtils - ManageEngine OpUtils is an IP address and Switch port management software that includes a comprehensive set of 30+ tools that helps network engineers monitor, diagnose and troubleshoot their IT resources.
Snipe-IT - Managing assets with a Google doc or a shared Excel spreadsheet is more common than you think.
BlueCat DDI - Unify your DDI (DNS, DHCP and IPAM) solutions to make DDI data an engine for innovation and growth.
Zabbix - Track, record, alert and visualize performance and availability of IT resources
phpIPAM - phpipam is an open-source web IP address management application (IPAM).