Unless you know the child well give £10 in a card and a bag of sweets - haribo, squashies, etc.
So many presents we were given in reception, y1 ended up being regifted. Unless you know the child well you don't know what they've already got, what they like, what they're allowed, etc.
When we've been given money we've put it together and bought something and put a message in the class WhatsApp to say what we've bought. Most others do the same.
My children are older now so know exactly what their friends like, but at that age, no matter how much thought you put into the present, you're taking a gamble!
All the people saying crafts, lego etc as a can't go wrong gift. I have two children who hate lego, one who hates crafts, even at a young age. There's no universal 'good' gift for kids.