7-tan, NT-tan, Vista-tan, XP Home-tan
These tags are mostly just used to collect characters with their own chartags based on what they're a personification of, despite them usually not being variants of the same character. My first thought was to deprecate them, but there's probably a niche use case for using them for designs that don't have a chartag of their own (vista-tan chartags:1).
My second thought was maybe to rename them to *-tan_(other) to be used only for these miscellaneous designs and not for characters that have their own tags.
XP Home-tan really should just be deprecated though, it's just a search for Homeko and Homeo. Everything without one of those two tags is still one of the two and is just missing the right tag. (It's mostly Homeko tbh)