Open DBDiff - A database comparison tool for Microsoft SQL Server 2005+ that reports schema differences and...
Zabbix - Track, record, alert and visualize performance and availability of IT resources
Redgate SQL Data Compare - Use Redgate SQL Data Compare to compare and synchronize static, lookup, and reference data in your SQL Server database - try it free
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.
DBComparer - Free Compare database tool - DBComparer 3.0 is a professional compare database tool for comparing Microsoft SQL Server 2008 (and 2005) database structure.
Prometheus - An open-source systems monitoring and alerting toolkit.