Cloudability - Cloudability lets you monitor, manage and communicate your cloud costs with one easy tool.
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.
Amazon CloudWatch - Amazon CloudWatch is a monitoring service for AWS cloud resources and the applications you run on AWS.
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.
CloudCheckr - CloudCheckr provides security, cost and usage reporting and analytics to help users manage their AWS deployment.
Zabbix - Track, record, alert and visualize performance and availability of IT resources