DD is 10.
Every year, she gets fruit and sweets (a mandarin, a perfect red apple, a perfect green apple, a banana, and maybe 1 other piece of fruit, and a proper treat type of sweets).
Every year she gets at least 1 book - a reading book she'll enjoy, and sometimes a more reference type book that she'd enjoy too (to do with a hobby or adventures or something) or a book of jokes or an Annual or a seasonal copy of her current favourite magazine/comic.
Every year she gets something "useful" - hair bobbins (we go through LOADS!), nice knickers, socks to make her laugh, sunglasses (lots of outdoor hobbies), or something else to do with her hobbies and sports activities. Magic flannels have made appearances some years, and gone down well. I know lots do new toothbrushes. Usually such items are "not quite" what we would get her, character items when smaller or maybe a step up brand-wise etc.
And then there are always quite a few fun things.
When she was that small, things like small garden tools (little shovel and fork and gloves) went down well for digging once the weather was dry. And were great in the sandpit too.
Bottles of bubbles to use outdoors - can be used on Christmas Day if fine, but always handy.
Colours - pencils, crayons, chalks for outdoors, ...maybe even paints if you are brave enough. Or other craft materials (glue sticks, coloured paper, lollipop sticks, stickers......all sorts can be used to bulk out the stocking and used for rainy days over winter/spring).
Small jigsaws.
A set of clothes for her doll (if she has one) or extra accessories (different food for a kitchen/shop, bottle or new nappies for doll, an extra few pieces for Playmobil or Fisher Price or Duplo sets, that sort of thing).
As she got older, some smaller toys that would get used, small cars, a stuffed animal, blocks, lego, and more recently things like slinkies and "grow your own crystals" set.
A little torch has been handy a few years, the one she powered herself (press the handle to charge the light) was the one she preferred most (and I didn't have to keep replacing batteries).
I haven't tended to get a lot of cheap tat for the stockings - more things that I know will get well used over time. So spending maybe €15/20 on the gardening set seemed extravagant to lots of my friends, but she has got years of use from it!