Not OP. I remember when I was little, playing computer games that were completely on the keyboard (we didn't even have a mouse.) They were stored on floppy disks and would start up by just inserting them into the computer. I'm not sure if you're asking as a fellow old-school gamer seeking nostalgic connections, or as someone who's never played old games and is simply curious, but I did find this list of early games pretty interesting.

There are a number of adaptations of classic arcade games, pop culture tie-ins, and even flight simulators. It amazes me how much floppy disks used to be able to accomplish.