What do we tag the kind of uniforms "magical girls" tend to wear in anime? japanese_schoolgirl_uniform? seirafuku? sailor_suit?

The only tag we have like that is school_uniform (at least right now). Do you ask because of the Kagome pic you posted? I left that tag off when I added some tags to it a minute ago, since you can't really see much of it.

I'm asking so I'll know if I post more schoolgirl pics. I was wondering if there was a different tag for Japanese Schoolgirl and the non-Sailor Moon-type schoolgirl uniforms.

As of right now, no there is not. It's all school_uniform.