Bmon
Tool to capture networking related statistics visually
Downtimed
System downtime monitoring and reporting tool
Goaccess
Goaccess can monitor Apache, Nginx and other web server log files
Icinga2
Inspect the Entire Infrastructure. Monitors availability and performance. Access to relevant data. Raises alerts in case.
MRTG
Monitoring SNMP network devices and draw pretty pictures showing how much traffic has passed through each interface.
Overview
An overview regarding monitoring solutions, the foundation of system administration
Smem
Report memory usage with shared memory divided proportionally
Zabbix
Installation of Zabbix on Debian 10 Buster