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.
Xen Orchestra - A complete web UI for controlling a XenServer or Xen infrastructure.
AppDynamics - Get real-time insight from your apps using Application Performance Management—how they’re being used, how they’re performing, where they need help.
SolusVM - Solus Virtual Manager (SolusVM) is a powerful GUI based VPS management system with full OpenVZ...
Zabbix - Track, record, alert and visualize performance and availability of IT resources
Virtualizor - Virtualizor is a powerful web based VPS Control Panel.