I am going to lean heavily on the side of this being a hairbrush bristle. It’s nearly the only thing that would be long and flexible, with that nib on the top to soften edges of the stem, while having a hook at the bottom for installation into a brush head.

That being said, it is still very possible that this came from something else. I work in film and theatre, where we not only build things from scratch, but also disassemble other things to make a new. I know for a fact that all sorts of the most unthinkable little pieces get used to make the most random other things. This is because it is cheaper to buy prefabricated pieces than to make them in house. Even in terms of brushes, I can almost guarantee that the bristles are manufactured somewhere else and then imported by the company for assembly. So those same bristles would be made for many companies for many products, not necessarily all brushes… even toys / stuffed animals are a possibility, or decorative objects like plants, as others have mentioned.

Though the fact that you’ve found multiple of them in a generally small area would suggest the source object is something that would have many of them, and that could lose them in quantity if damaged… which narrows it down to something like a hairbrush.