Forever Skies

Forever Skies is the most distinct premise in the whole field here. You and up to three friends maintain and pilot an airship above a ruined toxic Earth, scavenging ruins and managing disease alongside the usual survival systems. That vehicle-as-home structure creates a co-op dynamic you do not get elsewhere, everyone on board together with a shared stake in keeping the ship functional. It is not as expansive or as proven as the genre leaders, which is why it lands in the mentions rather than the list, but for groups that want something genuinely different from the standard wilderness sandbox, this is the one to try.

Forever Skies deserves attention because the concept is genuinely different: you pilot an airship over a ruined, dust-covered Earth, diving down into the toxic layer to scavage materials before your oxygen runs out. The survival pressure in those descent runs is real and the crafting loop for upgrading the ship is satisfying. It did not crack the top ten because the multiplayer side is limited to small groups and the content depth does not yet match the best options. For duos who have worked through Raft and No Man's Sky and want something with a similar exploratory feel but a different aesthetic, this is the obvious next pick.