I have a few family members who are teachers, and they ALL say chocolates, wine or a voucher! Basically something that can be used up.
They all say they don't expect anything, obviously, and really love a home made card and a thank you.
One received pyjamas one year! But honestly, most of the mugs, ties, gloves, photo frames etc go straight to the charity shop, as they just don't have room. Anything personalized with the child's name usually gets thrown away, because, really, they can't display it in school in front of the other kids, and who wants 30 poems about random kids in their house?
So, with the best will in the world, they all say vouchers (Amazon/coffee shop/local shopping centre) or something they can eat or drink!