There’s an aspect of worldbuilding that often gets left by the wayside because it seems irrelevant to the main characters and the plot, yet can do more than a thousand words to convince readers your world could be real.
Most books, even most written in the YA genre, don’t have children as main characters. And being a parent, practically speaking, does not lend itself well to adventuring.
(I can hear everyone who’s raised or even been roped into temporary babysitting groaning in agreement. Yep.)
So children are often tangential to a story plot, at best. Yet real worlds and societies have children. So they’ll have children’s toys and games. Anything else is not realistic.
Since kids want to grow up to be adults, and sane societies want them to, many toys and games are repurposed from Adult Stuff. Mini-hammers, drop spindles, shovels, you know. And even the more “toylike” toys of dolls, action figures, and wind-up cars help kids model real-life situations. For example crashing your cars can be Bad, look at what happened to the nice paint job….
An interesting aspect of any society is, how do we refine down very dangerous items, concepts, and processes so they’re safe to raise kids around? How do we make something perilous… a toy?
See sparklers. Substances originally meant to boom or burn, treated so they light with a match and throw off pretty sparks. Yes, they’re too dangerous for tiny kids. But older ones who know fire burns, and you can’t let sparks fall on flammables like dry grass? We give them sparklers. The dangerous pyrotechnic becomes a toy.
Any realistic world should have potentially dangerous toys. Techno-wizardry, psychic materials, magically empowered rocks; yes, they might be as dangerous as nuclear fission IRL and therefore not toy-able. Yet. But if there’s a tech in your world anyone might get their hands on – and exotic powers of the mind, magic, etc. are often shown that way in-setting-
Then there should be toys. At least attempts at toys. Harry Potter has Exploding Snap, among other things. The Clockwork Heart has little birds weighted with ondium so they actually float. (And can be lost forever if you take them out without a ceiling, lighter than air metal does that.) Bridge of Birds had the Hopping Hide and Seek Game, that turned out to tell part of an ancient story of a ginseng spirit betrayed and taken captive.
Think of the special – dangerous – aspects of your world. Consider how long they’ve been around. And think of what it might take to make very low-powered, near-safe versions of it. For fun. For a toy.
Because that’s what humans do. We fool around. We poke things. We say, “Hey, watch this!”
And we hand our kids sparklers.
Your story world is your toybox. Make sure there are some actual toys in it!