You could give sort of gift basket for their classrooms, or for the group as whole. Make a basket with items like music CDs (kid favorites like "My Brother Eats Bugs" or something), arts and craft books, or activities for a rainy day books, with some cheap crafty items for a filler like googly eyes, construction paper, pipe cleaners, etc.
Another option is a big basket full of consumables...You know other moms will be bringing in tons of cakes, cookies, and candies for them. Make a big basket or some small baskets with coffee, cocoa, and flavored teas to go with. It will last a long time, and go well with all the holiday snacking.