Munin-plugins is a project mainly written in ..., it's free.
Custom munin plugins
This repository contains custom munin-plugins.
"Decent" or better quality:
proc_ - Monitor a process munin_plugins - Count how many plugins are linked up md_sync - Sync/recover progress of a md md_sync_speed - Sync/recover speed of a md
"Read first"-quality:
df_abs - Slight modifications to the original, including a "Total Capacity" scsi_media_scan - Display scsi media scan progress scsi_temp - Fetch temperature with sg_logs (a bit redundant) terminals - Count terminals running (pointless fun) vgs - Display free space on LVM volume groups vgs_used - Display used space on LVM volume groups