I taught Pre-K for 10yrs and the most common gifts were:
-Mugs
-Soaps & lotions
-Candles
(none of which I used... so my co-teacher always got DOUBLE)
We eventually started putting out a note after Turkey Day saying that in NO WAY were any parents expected to buy the classroom or teachers ANYTHING. But that
if they were planning on buying the teacher a gift, to instead buy the CLASSROOM a book or a game which their child enjoys.
(Not in the note we sent, but...) We also always enjoyed GC's to Duncan Donuts or Barnes & Noble.
I usually get my boys teachers GC's to DD's and put it into a hand written card thanking them for what they do for my kids & any specific nice/cute thing my children have said about them. (Ex "Wesley said when Sarina sits next to him at project time he gets very happy.")