Zabbix - Track, record, alert and visualize performance and availability of IT resources
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.
Datadog - See metrics from all of your apps, tools & services in one place with Datadog's cloud monitoring as a service solution. Try it for free.
Snipe-IT - Managing assets with a Google doc or a shared Excel spreadsheet is more common than you think.
Prometheus - An open-source systems monitoring and alerting toolkit.
NewRelic - New Relic is a Software Analytics company that makes sense of billions of metrics across millions of apps. We help the people who build modern software understand the stories their data is trying to tell them.