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.
UserVoice - UserVoice integrates easy-to-use feedback, helpdesk, and knowledge base management tools in one platform that empowers users to speak and companies to understand.
Snipe-IT - Managing assets with a Google doc or a shared Excel spreadsheet is more common than you think.
Freshdesk - Freshdesk is a cloud-based customer support software that lets you support customers through traditional channels like phone and email, social channels like Facebook and Twitter, and your own branded community
Zabbix - Track, record, alert and visualize performance and availability of IT resources
Zendesk - Zendesk is a beautiful, lightweight help-desk solution.