Ceramic or glass toys would last the longest. As long as one was careful not to drop or scratch them, the materials they are made of will last thousands of years.
Silicone is sensitive to light (so store away from light), but seems long lasting (from the quick search I did on Google).
Not sure about metal, probably depends on the type. Gold doesn't tarnish (that's why the Egyptians used it to make their stuff for the afterlife), but is very soft.