Amazon CloudWatch - Amazon CloudWatch is a monitoring service for AWS cloud resources and the applications you run on AWS.
Google StackDriver - Stackdriver provides monitoring services for cloud-powered applications.
StatusGator - Monitor all your hosted applications, vendors, and websites, and keep your team informed of outages. StatusGator is the world's premier status aggregator, status page, and website monitoring tool.
MongoDB Cloud Manager - Cloud Manager saves you time, money, and helps you protect your customer experience by eliminating the guesswork from running MongoDB.
DigitalOcean Monitoring - Collect metrics, monitor Droplet performance, and receive alerts when problems arise in your infrastructure—no configuration required.
AWS Config - Cloud Monitoring