- [glances](https://nicolargo.github.io/glances/) - Open-source, cross-platform real-time monitoring tool with CLI and web dashboard interfaces and many exporting options. ([Source Code](https://github.com/nicolargo/glances)) `GPL-3.0``Python`
- [Healthchecks](https://healthchecks.io/docs/self_hosted/) - Monitoring for cron jobs, background services and scheduled tasks. ([Source Code](https://github.com/healthchecks/healthchecks)) `BSD-3-Clause``Python`
- [Icinga](https://www.icinga.com/) - Nagios fork that has since lapped nagios several times. Comes with the possibility of clustered monitoring. ([Source Code](https://github.com/Icinga/icinga2)) `GPL-2.0``C++`
- [Kula](https://github.com/c0m4r/kula) - Lightweight, self-contained Linux server monitoring tool with real-time metrics `AGPL-3.0``Go/JavaScript`
- [LibreNMS](https://www.librenms.org) - Fully featured network monitoring system that provides a wealth of features and device support. ([Source Code](https://github.com/librenms/librenms)) `GPL-3.0``PHP`
- [Linux Dash](https://github.com/afaqurk/linux-dash) - A low-overhead monitoring web dashboard for a GNU/Linux machine. `MIT``Nodejs/Go/Python/PHP`
- [Monit](https://mmonit.com/monit/#home) - Small utility for managing and monitoring Unix systems. ([Source Code](https://bitbucket.org/tildeslash/monit/src/master/)) `AGPL-3.0``C`