and Sweet Dreams. All of them generally have roughly the same resale value on eBay. If you are ready to part with your newborn My Little Pony, you could earn between $100 and $200 on eBay.

and manufacturers developed shows based on toys—like My Little Pony and Transformers—that followed niche-marketing wisdom by appealing to just one gender, says Sweet. It was a boon for the toy ...