Ask HN: Dead Simple Self Hosted CPU/Memory Usage Tool for Linux?

Other than some beasts like zabbix (which I played with), what else is out there to monitor server stats like CPU usage, memory etc ? What is out there in 2019 ? Most of these tools are too bloated for my needs. I just want a dead simple tool that does server stats. Ideally, a lightweight agent should be installed on the server that periodically sends the stats to the service. Bonus points if API based so we can write our own UI if needed.