mammy last year I got ds a mixture of things that were more grown up and a few 'toy' bits - so things like a nice usb stick, some grown up stationery and art bits (this is a good time of year to pick them up cheaply in the supermarkets as they get rid of their back to school and uni stock!), a 4x4x4 rubiks cube, an Anker power pack (it's a brand that my tech literate friends all swear by, and they get to try lots of tech stuff so I go by their experience!), some cheap sports earphones, a little tripod and lens set for his phone, and so on. Sports direct has some good stuff - if he has a favourite football team then there are often branded bits like pencil cases or boot bags or training tops for less than a tenner,
And then a few toy bits - a football, a funny toy car (he's always loved toy cars, you can get hot wheels for a pound in poundland) - in fact a swoop around poundland did provide a good haul, including a whoopee cushion, a double pack of playing cards, some American sweets (much cheaper than buying at the supermarket or online) and more. Also got things like a lego set, a science kit, a couple of cheap dvds that I thought he would like, some books from the book people on offer, a Now that's what I call Music cd and a ps4 game.
(Hasten to say that this includes a lot of christmas presents, not just stocking presents if you see what I mean!)
Stocking presents I usually put in a comic that he will like, new pants and socks that can be worn that morning, ditto a new tshirt, then things like a novelty toothbrush (last year Home Bargains had great ones that were star wars light sabers that lit up and said star wars-y things at you for the 2 minutes you needed to brush), some new more grown up shower gel and deodorant, as a way of having more to unwrap but of things they'd be getting anyway...