I hear you, Lena! One of my kids has 4 teachers and 4 therapists, plus each of the other kids has 1 teacher. I do gift cards at the end of the year, but with so many people to thank I can't do it twice. Today I bought some cute cookie tins at Michael's for under $2 each, and I'll be filling them with brownie bites (baked in a mini-muffin pan with colorful paper liners). I'll scrap a tag and maybe a coordinating post-it note holder.
Some years when there were fewer people to make for I've done notebook/bookmark/magnet sets like this:
or a $5 giftcard and inexpensive decorated candle in a bucket:
