I have seen some good suggestions on here for teacher gifts, and since I have a daughter that teaches in Mississippi school system, I have seen her have her own children's uniforms clean and pressed, their outgrown coats and jackets and even their tennis shoes to give to needy children in her classroom. That is in addition to school supplies and snacks she provides for them.
So, I would say school supplies or a money card to any store would be much appreciated.