When my kids were small I found it so much easier to fill the stockings for the girls, I had to be a bit more creative to fill my sons stocking. Then one year my Mother had a lady make them stockins, they were huge so I had to find more stuff to put in them.
Girls according to their ages consisted of: hair accessories; unique pens/pencils; small notebooks; make-up; maybe a cassette (remember them); jewerlry; perfume; lotions and etc.
My son according to age: cars, trucks; pencils/pens of course something that had the camo design on it (one year that's all he wanted camo stuff).
I always put in some candy, sometimes the big candy canes; or the small candy canes and of course something of chocolate.