Rogue likes usually run on a toaster. What’re people’s favorites?
I have a huge soft spot for Crawl: Stone Soup. Runs in a browser, or probably even lower requirements if you download it. The game’s design goals want to minimize tedium and gotchas, so it’s pretty respectful of your time. Auto-explore and auto-travel are real nice. So is the global search for when you’re like “is there anything in this run with resist poison?”
I’ve played a little nethack, adom, and angband, but I always go back to crawl.
These aren’t as old as the games in the other replies, but I love Dungeonmans.
Approaching Infinity is also great if you would like to play a RL that is basically old school Star Trek.
And both games will run on anything.