For me, voices of the void. It had a new alpha update, v0.9.0, so I've been going through that. If you are going to try the game, keep in mind that it has a lot of easter eggs and random events that you might want to experience yourself for the first time. Keep external research limited to how to do the daily tasks (it is confusing, make sure to look it up for your version cause it has changed a lot), and also keep in mind that events start really slow.
For my wife, we are going through the Outer Wilds DLC. If you are going to try it or the base game, look up nothing, and you will appreciate the game fully.