A suite of Monitoring Plugins (formerly known as nagios-plugins)
Self-hosted, lightweight server and website monitoring and O&M tool
The open source post-building layer for agents
Monitor the stability of a Pandas or Spark dataframe
Floating window used to display current network speed, CPU & memory
Monitor temperature sensors, fan speed, voltage, load & clock speeds
Disk Inspection and Monitoring
The Active Monitoring System
The open source time series database
Open source monitoring system and time series database
Lightweight network IP scanner
Scouter is open source APM (Application Performance Management) tool
An eye on your system
Xray panel supporting multi-protocol multi-user expire day
An interactive NVIDIA-GPU process viewer and beyond
Free open source tool for real-time PC hardware sensor monitoring
The Open Source Security Platform
Application to comfortably monitor your Internet traffic
Status page with uptime monitoring & API monitoring as code
The Network UPS Tools repository
Real-time monitoring for Proxmox, Docker, and Kubernetes
GRBL controller application with G-Code visualizer written in Qt
A Python based monitoring and tracking tool for Plex Media Server
Apache HertzBeat(incubating) is a real-time monitoring system
A fancy self-hosted monitoring tool