Munin - PnP networked resource monitoring tool that can help to answer the what just happened to kill our performance
Zabbix - Track, record, alert and visualize performance and availability of IT resources
Timespinner - Timespinner is a Platform, Single-player, and Multiplayer Metroidvania video game developed by Lunar Ray Games for Multiple Platforms.
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.
Hotaru no Nikki - Hotaru no Nikki is an Adventure-based, Puzzle-Platform, and Single-player video developed by Nippon Ichi Games.
Prometheus - An open-source systems monitoring and alerting toolkit.