Ok, so since people didn't pick, I'll be picking. Keep in mind that, for this story, everyone except for the reader is a giant/giantess. Anyway, for the girls:

Highschool DxD:

Koneko and Asia:

(Might add a third character in, idk yet, but would have to be someone outside the ORC group)

RWBY:

Team RWBY:

Kill La Kill:

Mako, Ryuko, and Satsuki:

Rosario Vampire:

Moka (both), Mizore, and Kurumu:

And finally

Senran Kagura:

Team Hanzo:

Besides Highschool DxD, I might add 1 more from the RWBY universe, though idk who yet.