nfsen-ng - nfsen-ng aims to be an in-place replacement for the ageing nfsen.
glogg - glogg is a multi-platform GUI application to browse and search through long or complex log files.
Zabbix - Track, record, alert and visualize performance and availability of IT resources
BareTail - BareTail is a real-time log file monitoring tool. Features Real-time file viewing
FastNetMon - FastNetMon is a very fast DDoS analyzer with sflow/netflow/mirror support.
klogg - klogg is the fork of glogg - the fast, smart log explorer.