Check x509 Certificates Expiration
Nagios plugin for checking a Postfix greylisting policy-daemon
Plugins for Check my Website
Icinga2 exchange plugin for monitoring init services.
Linux monitoring script for Nagios/Icinga/Shinken
notss-eh - A not so simple event-handler for Nagios
Icinga plugin to check Netio PDU
Nagios plugin to check JSON attributes via http(s)