Hot Wheels
Mattel took the miniature model car market by storm towards the end of the 1960s when unveiled its initial Hot Wheels lines. These little die-cast speeders might have been in hot demand many decades ago, but given how many tons of the toy cars are manufactured to this day, their worth has been diluted significantly. That being said, there are several unique Hot Wheels models that will earn a seller a fair amount of money, but these are few and very far between.
Autographed Sports Memorabilia
Sports memorabilia that have been signed by legends of their respective history are objectively worth a lot of money. The problem comes in during the sourcing process, as collectors will need to spend a lot of time and money trying to get their hands on select pieces. Even when one manages to get something as hallowed as a Babe Ruth-signed baseball, they may struggle to pin down an interested buyer. This is thanks to the incredible amount of counterfeit sports relics floating around.