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 ^^')
I like Idler Auto-Battlers, if that’s a good description. Games like Dragon Cliff or Ghost of Dragon (both by the same devs).
A group of NPCs automatically fight indefinitely, gather loot and experience and while that’s going on you can manage a base or something, change the party, maybe some other stuff. A big part for me is also not constantly resetting to increase some multiplier, like you would in a Cookie Clicker, Leaf Blower Revolution or NGU Idle.
I need to find more games like this though. A lot of games on Steam in the Idler category are either clickers, which I don’t want or F2P, that seemingly try to get you to buy stuff.