For my ProxMox server stuff I went with Lord of the Rings. The idea being the servers would be locations and the VMs would characters.
So right now my main server is Rivendell, and my PiHole on it is Gandalf ("You shall not pass!" Heehee eventually he'll have OPNSense too...)
If I get HomeAssistant at some point, obviously that'll be Samwise!
My Klipper VM for 3D printing is Celebrimbor, and the individual printers are named after various deities or myth figures of crafting/smithing/creativity like Brigid and Eitri.
For my client devices, I name my personal hardware after BattleTech mechs and that works well. It's intuitive because I can line up various roles and weight classes.
So my main desktop is Timberwolf, and my laptops are named after light mechs like Kitfox or Mistlynx.
Phones and tablets I don't really care about, they usually just name themselves after their model anyway. :)