T.N.
Well once my kids got to middle school, they could have up to 20 different teachers/staff members each a year (and there's three kids!)!
So this is what I started doing (and still do). I buy 9 $10 Dunkin' Donut gift cards. So each kids picks only 3 teachers to give a gift to. The KIDS fill out the cards, write something nice, include the gift card, and that's that!
I also have taken to sending personal 'thank you' emails towards the end of the year to teachers/staff members my kids talk a lot about or really like.
:)