My son is starting at a pre-school that is a parent co-op. Parents have to volunteer in the classrooms once a month, as well as providing the snack that day. I am parent helping on the first day of school, and trying to figure out something fun to bring in!
Low- or no-sugar
I think they try to avoid peanuts, but are not strictly nut-free unless a student attending has a nut allergy. I have e-mailed the teacher to verify.
I'm supposed to provide two items, at least one should have "universal" child appeal.

I mean, I could do cheese sticks and clementines, and I probably will next month, but I thought I'd try to think of something a bit more fun for the first day of school!

Bonus: His class name is the bumblebees. It might be fun to incorporate, but definitely not necessary.