What film, show or game that is not necessarily 'underated' didn't have the level of social impact it deserved.
What's the antithesis of Arrested Development, Firefly or The Big Lebowski? Those may never have 'found their audience' but over time seemed to recognised by everyone. What are the deep cuts that you liked but it feels like everyone has completely forgotten they even existed.
Star Wars Galaxies. It really was really lightning in a bottle. No other game has come close to recreating the social player-driven sandbox experience that was SWG. This was the first MMORPG I played to feature a classless build system and I haven’t played another game which does it quite as well. Honourable mention goes to the Jump to Lightspeed expansion, truly the coolest expansion for any game I’ve ever experienced. We will never be able to recreate the experience of SWG again, the culture of gaming has changed too much. It was a game where you simply couldn’t solo the entire game or hang around with a dungeon finder or anything like that. You had to interact with other people - you had to kick back and hang out in bars together, you had to ask someone to help you change your hair colour or style, you had to ask doctors to heal you, or tailors to make clothes for you in a style you liked, or settle for off-the-rack fashions bought from player-owned stores. Players would also take the role of bounty hunters to hunt down criminal players for credits. You’d get to know a lot of the people you shared a server with, you’d remember who was fun to team up with, or who saved your ass, or who gave you some buffs, etc. and it really made the experience unforgettable.
Shit, close to 10 years after we stopped playing, my wife was playing WOW and someone was all, "Icarii... from Corbantis? I bought so many weapons off you, yours were the best!"
I have good news for you! SWGEMU dot COM. Development has been going on for damn near 20 years now. Hope you have your original install discs or it'll be the high seas for you, mate.