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 ^^')
Have you played Acid Spy ? If not, you can pick it up for ~6$ during sales on steam. Despite being very short it’s well worth it !