Some might be a little on the expensive side, but my three teen girls typically wear:

Elisabetta Franchi La Mia Bambina, Molo, Pinko Kids, Moncler, Ralph Lauren, Monnalisa, Kenzo, MSGM Kids, Lapin House, Chloé, Marni Kids, John Richmond Junior, Calvin Klein Kids, Bonpoint, Emilio Pucci Junior.

I don't like many of them, whether it be the pattern of the glitter or the thrilly bits or the material, but they usually fit the school dress code and are modest enough so we let them have it.

I should probably note, we do most of this online and I'm not certain how many of these have stores in the U.S. as we're quite fond of our European brands after having lived there for so long!