I know most of the Bethesda RPGs have massive mod support, and there’s games like Minecraft that have more mods than anyone can imagine. I would consider those games pretty playable in their vanilla states. Would you say there are any games that were “saved” by modding? Or that are still kept alive by thriving modding communities? What are some of your favorite mods?
Seconding Rimworld, but even without mods it is an amazing game with easily 1k+ hours of gametime. My favorite mods are QoL mods, or ones that add additional flavor to my colonists. If I could only pick a single mod to install, ever, it would be Common Sense.
Outside of Bethesda and Minecraft, the other one that comes to mind is The Sims. More of a niche following, but for those that love deleting pool ladders, mods are necessary for happiness, flavor, and adding actual challenge.