Zabbix - Track, record, alert and visualize performance and availability of IT resources
WatchDirectory - WatchDirectory monitors a file system directory and performs tasks when certain conditions are met.
Abusix - Abusix is a network security company that offers email threat protection and network abuse handling solutions to ISPs, Telcos, and Cloud/Hosting Providers to stop the rapidly growing problem of email-borne threats and other kinds of network abuse.
Watch 4 Folder - Watch 4 Folder is a simple to use, small and portable tool to monitor folders and file activities.
Easy-IP - IPAM and DNS for Telecoms
iWatch - iWatch is a realtime filesystem monitoring program.