Raygun - Raygun gives developers meaningful insights into problems affecting their applications. Discover issues - Understand the problem - Fix things faster.
nxlog - NXLog offers log management solutions for companies of all sizes.
Kafka - Apache Kafka is publish-subscribe messaging rethought as a distributed commit log.
Kiwi Syslog Server - Kiwi Syslog Server prvides solution to centralize and simplify log message management across network devices and servers.
Snare - Snare is well known historically as a leader in the event log space.
rsyslog - Rsyslog is an enhanced syslogd supporting, among others, MySQL, PostgreSQL, failover log...