That or modding. Modded Minecraft is done purely because someone wanted to have the functionality of magic wands or engineering or resource processing in their lego game. It's completely unmonetized and gets extremely involved very fast. I fondly remember my nuclear reactor exploding and having to work around the irradiated zone. Good times.

the indie scene may be greater for that but is also filled with the same money making trite and on top of that constantly copying each other and barely doing anything new.