I'm in the process of getting my Home Assistant environment up and running, and decided to run a test: it turns out that my gaming PC (custom 5800X3D/7900XTX build) uses more power just sitting idle, than both of my storage freezers combined.
Background: In addition to some other things, I bought two "Eightree" brand Zigbee-compatible plugs to see how they fare. One is monitoring the power usage of both freezers on a power strip (don't worry, it's a heavy duty strip meant for this), and the other is measuring the usage of my entire desktop setup (including monitors and the HA server itself, a Lenovo M710q).
After monitoring these for a couple days, I decided that I will shut off my PC unless I'm actively using it. It's not a server, but it does have WOL capability, so if I absolutely need to get into it remotely, it won't be an issue.
Pretty fascinating stuff, and now my wife is completely on board as well; she wants to put a plug on her iMac to see what it draws, as she uses it to hold her cross-stitch files and other things.
If you want to expand from just monitoring a couple sockets to monitoring the whole house; I'd recommend Iotawatt. I've been using one of these to monitor every circuit in my house for a few years now.
You can use the built in webpages shown below to view it's internal graphs, or setup an exporter to feed the data into external DBs like influxDB+Graphana or Emoncms.
Very cool! However, my house is a rental, so any monitoring equipment has to be somewhat non-invasive.
Edit: it helps if I actually look at the product before spouting nonsense... Looks promising.
I'm in a rental too. It's non-invasive; just gotta pop the panel cover off, clip the transformers over the wires without disconnecting them, and put the cover back. It can all be removed just as easily.