I if I had to pic just one, Serial Experiments Lain would be one of the safe choices. Not only was it way ahead of it’s time, going as far as to predict online movements like anonymous (knights, in the series), it has many themes that are relevant to this day.

One less known piece is Cloudpunk. This game made me legit fall on tears. It’s about how little people carry on under a capitalist dystopia. Which is basically almost how things already are but with flying cars.