logstash - logstash is a tool for managing events and logs.
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.
rsyslog - Rsyslog is an enhanced syslogd supporting, among others, MySQL, PostgreSQL, failover log...
Syslog-ng - Syslog-ng decreases the quantity and improves the quality of data, thus enhancing the capacities of your SIEM solution.
Graylog - Graylog is an open source log management platform for collecting, indexing, and analyzing both structured and unstructured data.
Fortinet FortiAnalyzer - Fortinet FortiAnalyzer is a powerful product for Security Fabric Analytics and Automation.