To decrease this behavior you can limit her access to small movable objects. Put toys away after play time, and pick up small non-toy items and put those away too. This will not train her not to do it, it will simply prevent her from practicing the behavior.
This type of caching behavior in carnivores is instinctive and serves to fulfill the primary motivation of feeding. As such is not a good candidate for training ‘not to do’. Instincts that satisfy primary motivators (feeding, fighting and, procreation) are subject to ‘instinctive drift’. In other words the training doesn’t stick, and the behavior always returns. It is better to prevent her from engaging in the behavior by taking the toys away.
I’ve had cats bringing me toys in bed or on the couch when they want to play. Try throwing the things she brings. If you can get her to chase things she brings to you, you can shape this behavior into a game of fetch, thus redirecting her unwanted behavior into something more acceptable.
Read more about instinctive drift here: