My DS will be 19 in December so a little bit younger.
I've asked him tonight for a list . There's no point me trying to guess. (I know what 16yo DD likes or she'll 'helpfully' point things out )
DS doesn;t like shopping, not interested in brands (which is nice )
I've bought him a couple of sweatshirts from H&M (to wear now) so if he likes them, I might buy more.
In his stocking he'll get:
Money (he always gets a £50 note)
Underwear (H&M and maybe a brand if I can find some nice ones that will fit him)
Showergel/smellies
Sweets
Viz annual 
He plays the guitar , we pay his lessons . He's thinking about buying another guitar .(So we might buy him one or give him money towards it)
Maybe a voucher for the trendy mens' barber.
He's got a new beard trimmer and electric toothbrush .
He doesn't want a new wallet , he has an iPhone 7 that he's happy with.
He rarely drinks alcohol and never coffee .
I think he'll get money+vouchers unless he thinks of anything (little bugger will get a lump of coal at this rate
)