I am unsure which site it'd be, but heard from an acquaintance that apparently a lot of old Nintento (8 bits) and Super Nintendo (16 bits) are online now. I don't know what URL that'd be though, but if it's even remotely true, I'd browse there ASAP.
I am a child of the late eighties and nineties (born in 1981 so childhood and puberty in late 80s and 90s) and all stuff from that era, even the guilty pleasures, make me nostalgic: Eurodance (I don't think stuff like 2 Brothers On The 4th Floor, Cappella, Dr Alban, Haddaway, Whigfield, etc would be "good music" really, but the nostalgia element makes me enjoy it whenever I hear it on the radio) , images of the 90s football/soccer games that occasionally get repeated on TV, ... and yes, video games!
As a kid and teenager, I spent hours and hours every week on Nintendo, Game Boy and Super Nintendo. I remember how PacMan and Tetris were still considered "high tech" when it comes to quality of images... My biggest addictions were all Super Mario Bros. games: Super Mario Bros 1 + 2 + 3 (all on Nintendo), Super Mario World + Super Mario Kart (both on Super Nintendo)... Super Mario was my priority, the memories make me nostalgic about childhood again
Other games I remember well: Street Fighter II, Lemmings, MegaMan, ...
Then there were the early games for PC (which back then was Windows 3.1
): "Cats", "Minefield", "Tetris", "PacMan", different card games, a few very early tennis and soccer games, Sim City, a racing game which included the option to build your own race track and then race against a friend or against the computer, ...
I'm getting melancholic here
Would be awesome to play those games again, even if only a minority of them would be online!