Mine is vehicle building games like Stormworks or Scrap Mechanic. It’s so much fun to shoot at your friends with your latest nuclear drone while hiding in your bunker with a better defence system than Area 51 !
I’m very curious about your fav niche game genre !
(I’m sorry for my bad English ^^')
Sandbox RPG games with deep simulation and emergent gameplay elements cranked up to 11. Stuff like Dwarf Fortress, Kenshi and to some extent RimWorld.
I don’t know if there is a name for this genre and if anyone has similar games to recommend, please do!