productboard - Beautiful and powerful product management.
Zabbix - Track, record, alert and visualize performance and availability of IT resources
Hassl - A really great project management app
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.
Arbor - Easily manage product development
FastNetMon - FastNetMon is a very fast DDoS analyzer with sflow/netflow/mirror support.