Stellaris

This is a /v/ related article, which we tolerate because it's relevant and/or popular on /tg/... or we just can't be bothered to delete it.

As if creating Crusader Kings, Europa Universalis, Victoria and Hearts of Iron wasn't enough, Paradox Interactive decided that space literally was the limit, setting out to make a 4X game set in the vast reaches of the cosmos. It's notable for /tg/ in that it can be used to fit almost any sci-fi archetype. Do you want to play as the Imperium of Man and purge all the filthy Xenos for the God-Emperor? You can do that. You want to play as the Federation and create a noblebright union of alien species working together for the greater good? You can do that too. With a large selection of DLC and fan mods available (including explicit 40k based mods) Stellaris is an incredible sandbox for creating grand narratives of the rise and fall of interstellar empires.

On the downside the cost of the paid DLC can be considered almost criminal.