OK, let me fix that for you permanently.
This is Retroachievements.org.
Not only does it do what it says on the tin, but it's, for my money, the best discoverability tool out there for old games. The most obvious way to use it for that is to check the new games they've added achievements to, but they also have book club-style events (they're revisiting F1 games this month to go with the movie currently in theatres), challenges, seasonal achievements, leaderboards and all sorts of the types of metagaming stats tools you've seen in modern platforms to point you in the rigth direction.
You can start by selecting "all games" and sorting them all by players to see what's popular. Or, hell, reverse sort by players and see what weird crap is in there. Once you start down that rabbit hole you're more likely to have too much in your retro backlog than you are to ask this question again.