S.
My son loves cars, too, so I catered to this obsession... books about cars, coloring books about cars, stickers, etc. I also found that Match Box & Hot Wheels have some sets to be used with the cars... they are a car wash, a snake bit, a police station, etc. One popular item seems to be the Stinky Garbage truck.
How about the Fisher Price garage? My son uses many of the Fisher Price things (school bus, castle, fire station) with & without his cars.
He also loves Legos (Duplo kind), the Fisher Price medical bag, pretend tools (usually fixing cars or something else around the house) & pretend food.