Since I have a second grade boy I can tell you what toys lasted-as far as what he wanted to play with- the longest.
The wooden trains- Thomas, Brio played with for years and then you always have something to buy since there is a million things
The FP little people like the ship or the especially the parking garage if they still make it, that got lots of play time,
Playmobil ! Anything their stuff is great and they make a wonderful line for toddlers. alot like FP but nicer. They have a train, farm, cars etc. My son loved his and then as he got a bit older moved onto the regular Playmobil and still plays with it, has the castle, train, crane, vikings, etc.