ServerSuit - ServerSuit is a browser based program that enables remote Linux administration, monitoring, website hosting, and server setup automation.
Nessus - Nessus Professional is a security platform designed for businesses who want to protect the security of themselves, their clients, and their customers.
Nagios - Complete monitoring and alerting for servers, switches, applications, and services
AlienVault USM (from AT&T Cybersecurity) - AlienVault USM Anywhere delivers powerful threat detection, incident response, and compliance management for cloud, on-premises, and hybrid environments.
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.
Tenable.io - Tenable.io Cyber Exposure platform helps to protect any asset on any computing platform and eliminate blind spots.