This might be just spam and everyone might already know about this, I which case I'm a huge dummy but:
playdosgamesonline.com (http://playdosgamesonline.com)
I only just found this site yesterday and it lets you play any of 3800+ old DOS games on your browser without any need for downloading the game or emulators...
I just played Cruise For A Corpse, Oregon Trail, Sam And Max, and Nuclear War, all in my browser!
And there are so many more I must search out and play again!
Sorry again to those probably most of you who already know about this or similar sites but I had no idea, and so at least someone else on here maybe didn't as well...
Now I head back out on the Oregon Trail... (Perhaps Mandle, Andrea, Mark, Ali and Cat won't die this time... (laugh) )
I can do one better with 3999 games: archive.org (https://archive.org/details/softwarelibrary_msdos_games)
You can also look up old magazines, videos, audio, software, basically anything that's over two decades old and has long since been abandoned.