Decent socks, tights, underwear, a jumper that fitted and wasn't made of nylon, shoes that fitted, a waterproof coat, gloves, a hat, scarf, waterproof backpack, a lunch box, a flask and things like colouring pens, pencils and paper.
And access to toiletries that were for me, nobody else - so toothpaste that didn't burn my mouth, a new toothbrush every six months, introducing the concept of flossing or using interdental brushes dentist visits would have been nice, soap, shampoo, conditioner, a comb and brush, proper covered hairbands, facial cleanser and moisturiser as I got older. Although I'd have also needed access to showering facilities and a hairdryer, too, as hot water cost money and a hairdryer was beyond my wildest dreams - you'd have to show me how to use a shower, though.
From working in a school, though, I think the most needed are small washbags of toiletries (travel size ones are great) and socks+gloves (fingerless as an option). Everything feels better when you're clean and your feet and hands are warm.
ETA: I almost forgot. Plasters. At least with your own collection of plasters and 3 inch adhesive wound dressings, the holes that had been cut into your feet by the shoes could heal without your cheap, crunchy socks getting glued to the scabs and having to peel them off every evening.