My dd is 10, she really enjoys board games. Some solo ones we have are Simon Air, bop it, silly sausage, rush hour, screwball scramble. Ive got her cat crimes for Christmas morning.
Or if you wanted family games she really likes the big potato ones, we have chameleon, OK play, colour brain junior, what came first. Or we like cluedo, monopoly (got her dinopoloy for Xmas!), payday, exploding kittens, uno, dobble, pictureka, game of life.
I buy all our board games in the charity shop or from vinted. Usually games are in very good condition. I always check contents to make sure its all complete.
Or otherwise would he enjoy some fossils or crystals? My daughter wants some geodes you crack open yourself. She has quite a collection of fossils and crystals.
Origami set? My eldest daughter enjoyed these. She also had a great book of paper planes. Had loads of printed paper and instructions to make different planes. Think it was usbourne.
Is he into pokemon? Maybe some cards.
Or does he like any films/TV series. You can get funko pop mystery minis or mystery figures for quite a few. My eldest likes opening them and displaying in her room. I've bought lots from toysforapound.com in the past.