I've been enjoying playing a single-player/small-scale multiplayer mod of Ultima Online inspired by the early Ultima games called Ruins & Riches. If you have nostalgia for Ultima and/or Ultima Online I strongly recommend it. It doesn't have a dedicated webpage anymore, but there's some reddit posts describing it's current state, see e.g.: https://www.reddit.com/r/ultimaonline/comments/10axsri/ruins...