In addition to a few I’ve seen posted already (Stardew Valley especially)…

• A Dark Room: A relatively short, minimalist, mostly-text-based RPG with a dark vibe. I come back to this at least once a year. Can be played free via web browser, but the native app version has some extras.
• Dysmantle: A huge and well-polished zombie survival sim. Just recently finished it and was really impressed with the overall scale, level design and progression.
• Papers, Please: A ‘dystopian document thriller.’ You play as a border checkpoint agent, verifying increasingly-complicated passport documents and questioning your moral compass. Port of a PC game by the same name.