Wazuh - Open Source Host and Endpoint Security
Pingdom - With website monitoring from Pingdom you will be the first to know when your website is down. No installation required. 30-day free trial.
Beats - Beats is the platform for single-purpose data shippers that is installed as lightweight agents and send data to machines to Logstash or Elasticsearch.
StatusCake - Website Uptime Monitoring & Alerts – Free Unlimited Downtime Monitoring
Syslog-ng - Syslog-ng decreases the quantity and improves the quality of data, thus enhancing the capacities of your SIEM solution.
Better Uptime - We call you when your website goes down