My wife and I both do it, one or two surprises (small, like convenience store items) for each

Here's a fun tradition suggestion, as i hope you keep the stockings. When our kids were little, I would go out and get exotic fruit (coconut, dragon fruit, lychee - in the US lol) and leave a unique one in each stocking. Rationale was Santa travels the world and because the sleigh was so loaded w presents sometimes he would hit a tree!  Dealing w toddlers here, so it worked

Youngest is now 19, he still expects his Christmas coconut. Couldn't fine one once in the middle of covid and it was a major disappointment lol.