A extra hat because babies pull off their hats and pull them off to discard them in the aisles of grocery stores, on the floor of the car, and/or at the playground. (Bonus tip: because they get lost so easily, buy some inexpensive ones at the thrift store! I found a really cute penguin hat for $1 at our thrift store.)
Applesauce pouches. It's relatively mess-free, and a kid can eat it with mittens on!