cpustat periodically reports the current CPU utilization of running tasks and
can optionally report per CPU and per task utilization statistics at the end
of a run.
cpustat has been designed and optimized to use a minimal amount of CPU cycles
to monitor a system hence it is a light weight alternative to traditional
process monitoring tools such as top.

Eventstat periodically dumps out the current kernel event state.It keeps track
of current events and outputs the change in events on each output update.
The tool requires sudo to run since it needs to write to /proc/timer_stats to
start and stop the event monitoring.

Fnotifystat periodically dumps out the activity on files in the system. It can
be used to identify rogue file activity and discover which processes are
performing open/close/read/write operations on the files.

Forkstat monitors process fork(), exec() and exit() activity. It is useful for
monitoring system behaviour and to track down rogue processes that are spawning
off processes and potentially abusing the system.

Health-check monitors processes and optionally their child
processes and threads for a given amount of time. At the end
of the monitoring it will display the CPU time used, wakeup
events generated and I/O operations of the given processes.
It can be used to diagnose unhealthy bad processes.

Kcollectd is a graphical KDE-frontend to collectd that allows to view RRD files
that have been created by collectd.
It allows to easily navigate in the data with the mouse and can be used as a
chart recorder.

Interactive kernel monitor that combines dmesg and kmod.

libfixbuf is a compliant implementation of the IPFIX Protocol, as defined in
RFC 5101. It supports the information model defined in RFC 5102, extended as
proposed by RFC 5103 to support information elements for representing biflows.
libfixbuf supports UDP, TCP, SCTP, TLS over TCP, and Spread as transport
protocols. It also supports operation as an IPFIX File Writer or IPFIX File
Reader.

ipfixDump is a command line tool for printing the contents of an IPFIX
file as text.

This plugin checks the hardware health of Adaptec Raid controllers with the
aaccli software installed. It uses the aaccli command to acquire the
condition of the adapter's disks and containers.

A Nagios plugin to monitor Cisco UCS rack and blade center hardware.

An Icinga/Nagios plugin to monitor resources on Microsoft Azure.

This plugin checks various parameters from DB2 database servers.

This plugin checks the hardware health of Fujitsu servers (using SERVERVIEW-STATUS-MIB)

A generic plugin for Icinga/Nagios which checks json values from
a given HTTP endpoint against argument specified rules and
determines the status and performance data for that service.

A plugin, which is used to monitor various parameters of a IMAP server.

A Nagios/Icinga plugin for checking connectivity to an MQTT broker.
Or with --readonly monitor an mqtt application. Or for checking the
status of MQTT clients maintaining the status on an MQTT broker.

This plugin is used to monitor a variety of MS SQL Server database metrics.

This plugin checks the security level of your Nextcloud instance
with the Nextcloud Security API.

It check uses Nextcloud's own security scan at scan.nextcloud.com to
check if your Nextcloud instance has any known vulnerabilities/risks.

A nagios/icinga plugins that checks the network time.

This plugin checks the hardware health and various interface metrics of
network components like switches and routers.

A monitoring plugin to check components and health status of systems
which support Redfish.