RPG Mafia was a blast. (The sequel, not so much.)
Good vs Evil, Chaos vs Law was also a great game, aside from the shitty Chaotic Good town (save Regfan, the credit to his kind) being shitty, despicable human beings.
Happy Tree Friends was an amazing game.
Mind Reader Mafia had an absolutely
brilliant
concept.Anything Goes is seriously one of the best games of all time. Both teams were comprised of absolutely fantastic players.
Antihero Mafia Reboot was also an awesome game.
Xenogears was another instance of top-tier players on both teams playing strongly.
I loved Mobile Suit Gundamn, in spite of the scum dayvigging me D1 (because I had the best reads).
Left 4 Dead will forever be remembered by me as the game where I trolled the fuck out of the town as confscum.
Attack on Titan was one of THE best games ever played, with the closest, hardest-fought battle of all time. If not for displaced replacing in, the scum would've won the mylo...in spite of all three scum having been the top three wagons D1. (Which they turned around into a mislynch.) Strong play by both sides, really great game.
Paranoia is another of those games which had an AMAZING concept behind it, regarding the scum.
Duck Tales Mafia remains a classical favorite of mine.
Drawn on Arrival featured some of the BEST townplay and town cohesion ever and is another.
Inorganic Chemistry was another great game where both sides played well.
It's hard to forget Steven Universe, as that was a pretty amazing game.
Those as a player. As a mod, it's hard to decide.
From a mechanics point of view, probably Hilariously Unbalanced Mafia 2.
From a gameplay point of view, probably Maniacal Street Mafia.
From a flavor point of view, hard to beat Gistou.
Though any of those three games could fit for the other two just as easily, albeit in different ways.