Lots of good games on this list, no need to repeat, but I'll toss one out I haven't seen yet:

Rimworld.

A base-builder, it's similar to Dwarf Fortress (without the difficulty of trying to figure out which Unicode symbol means "wheelbarrow") and allows you a pretty high degree of freedom in crafting whatever life you'd like for your colonists.

I've had one game where I worked as the paragon of the people, healing any tribespeople who attacked me and sending them back to their people to speak my praises. I would recuperate them in my Tier1 medical facility, complete with bionic legs and eyes and whatever else they lost in the fight between their spears and my plasma rifles.

On the other hand .... there was definitely one game where we huddled in the frozen tundra, dug our way into a mountain, and started manufacturing cocaine grown in hydroponics vats to support our quest for world domination. And in that one, we preferred to harvest the organs of people who attacked us, and their tribes never saw them again.

Certainly morally ambiguous, very open-ended, and a ton of fun.