CPU-Z - CPU-Z is a freeware that gathers information on some of the main devices of your system : Processor name and number, codename, process, package, cache levels.
Zabbix - Track, record, alert and visualize performance and availability of IT resources
Speccy - Speccy - find the details of your computer's specs. Great for spotting issues or finding compatible upgrades. Download the latest version free.
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.
AIDA64 - AIDA64 is a system information, diagnostics and benchmarking solution for Windows PC.
Prometheus - An open-source systems monitoring and alerting toolkit.