Golden Leaves
In Jack and the Beanstalk, these leaves are a source of temptation and greed. Jack's mother is eager to get her hands on them to leave a life of destitute, but her eagerness to sacrifice her own son by climbing up the stalk, becomes the reason for her own demise.
Giant
The Giant in this case could actually be an allegory for the concept of God. He resides all the way to the top of the Beanstalk and seems to serve his punishment to those who deserve it, like Jack's mother, and reward others, like Jack himself.
Glass Slipper
The Glass slipper is a motif for the idea of a perfect fantasy. The glass slipper is beautiful, but rigid in its structure - often times, one may not be able to fit into the slipper, and therefore they have to make their own path.
Red Riding Hood
The Hood that Red wears is in her namesake color, and may actually symbolize her bloodthirsty nature. Perhaps, even, her cloak is red because of all the blood it has soaked from her huntings.
Magic mirror
The mirror may represent the ability to make use of your resources. Snow White used the mirror to her favor to curry favor with the dwarves, and eventually ended up becoming wealthy as a result.