In terms of toys which my son got from my childhood, Duplo and Lego stick out. We kept everything; booklets and parts. We built the classic town square (set 1592) recently, and we've got all the parts, including the statue bits! Only the printed lettering on the sign's 1×8 white brick had faded.

Sure, some puzzles and books survived, but the Lego stands out. If he ever has children they are in for a treat…