Inventory items that affect need and mood?

I don't know of any mods off the top of my head, other than possibly the glimmerstone overhaul mod (I don't remember any details), but it more than likely won't require scripts. Scripts are only for injecting stuff into the game to avoid overrides, changing EA's scripts, or adding stuff that normally isn't possible with tuning or is tedious with tuning (and there are some people who just prefer to do everything with scripts, not that it was necessary).

I've seen tests to check for inventory items before, and I know that objects can directly give buffs through broadcasters, but I'm not sure if broadcasters work from the inventory. I can't think of any EA items either, maybe one of the rocks that involve aliens? Earbuds maybe, since they play music while they are in the inventory. I went ahead and took a look, I don't see any objects with just buffs directly in the files, but there are several objects that have broadcasters (that have loots, which give buffs) and can go into the inventory, the Earbuds being one. So if you are making a new object, or overriding objects, you can take a look at the earbuds on how to build your object's tuning so that the broadcaster applies the buff to children when in their inventory. If you don't want to change the tuning or make new objects there are several ways I can think of doing this but I wouldn't know what to suggest that fits into whatever your idea is. One idea is that you could do a "this is my favorite toy" interaction that could have a hidden trait with a buff that tests for that specific object. Or if you truly want to script, you can of course look into injecting the broadcaster or use a script to look for a toy in a child's inventory and applying the buff if present (last one probably be more difficult). Or another tuning option is to do it with a commodity but you'd have to apply it to the sims you want, but how you apply it is the question as there are several ways. But those are just a couple of options I can think of.

Depending on what you want it to do can change how you make the mod. But here are some modding resources (tuning and scripting) under the spoiler, start with a tuning angle first as it's far easier (unless you have experience in Python/other languages):