The little car in 6374 (I'm an 80s-90s kid). Even after 30-odd years.
If looking at a photo is allowed, I can build an approximation of the 6374 house. Well, I'd forgotten some important details (it's been *decades*) but since I found instructions online last year & rebuilt it a few times I'm confident I can now build that house if I start from the second floor plates.