Before DH and I had kids, we tried to get through AFI's 100 greatest movies. We never quite finished, it might be fun to start or to watch with the kids (the appropriate ones, of course)
https://www.afi.com/afis-100-years-100-movies/
I just checked the list and looks like I've seen at least 73 (some of them I can't remember), plus I'm sure the list changed a little from 15 years ago.