If it has a graphical display, the name must match the wallpaper, and the wallpaper must match the desired aesthetics.
So eg. my current phone is red, so it has Selesia Upitiria from Re:Creators on a wallpaper, and hostname is selesia.
My thinkpad is dark and tough, so it has Batou from GitS on wallpaper, hostname batou.
My bigger laptop has blue backlight on keyboard and back-of-the-screen logo an has a spaceship-y look, so it has the Prometheus spaceship from Stargate on the wallpaper, and hostname is prometheus.
Now, things which don't have a screen, like servers, routers, switches, etc. I just name after any anime character.
Managed switch is tachikoma (from GitS)
OpenWRT router is integra (from Hellsing)
VPS used to be faris (from Steins;Gate) but she's dead now.
@gaige I never change wallpaper.
(possibly relevant: I never change avatar either)
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