Serilog - Backend Development and Utilities
logstash - logstash is a tool for managing events and logs.
LogTailApp - LogTail is a local and remote (SSH) log file viewer and monitoring application for Mac OS X. It is a pure, modern, document-based Cocoa App
rsyslog - Rsyslog is an enhanced syslogd supporting, among others, MySQL, PostgreSQL, failover log...
Logmatic - Logmatic is a log centralization, analytics & visualization platform to improve software & business performance.
Graylog - Graylog is an open source log management platform for collecting, indexing, and analyzing both structured and unstructured data.