I have done a blog series about collecting and displaying performance metrics from a vSphere environment with tools like PowerCLI, InfluxDB and Grafana.
The PowerCLI scripts that are used to collect the metrics are found on GitHub
At VMworld Europe 2018 I did a session based on this series which was recorded. Check this post for more information and link to the recording
Hopefully the series can give you some ideas and inspiration on how to do performance monitoring in your environment