Network intrusion detection tools
Scirius (Suricata rule management)
Scirius is a web application to do Suricata ruleset management. There is both a community version as paid version available.
Suricata (network IDS, IPS and monitoring)
Network threat detection engine that acts as intrusion detection (IDS), inline intrusion prevention (IPS), and network security monitoring (NSM)
Sweet Security (security monitoring on Raspberry Pi and similar)
Sweet Security is a set of scripts to setup and install Bro IDS, Elasticsearch, Logstash, Kibana, and Critical Stack on any device.