So there's this fun, really old, but free game called Noctis 4. Its technically multiplayer, because the game sends the new names of discovered objects to everyone, but there is no interaction, as there are 100,00 procedural stars and probably only 10 players. It also procedurally generates unique life on these planets. Its like nomans sky, but without the hype and the price tag. The only caveat is the graphics- which are slightly low resolution