City builders. Now I know it's a though genre to get right, it's hard to strike balance between simulation and "arcade" but it's still weird to me that modded SimCity4 offers a more complete experience than Cities Skylines, 1 or 2 (random examples: industries in CS1 doesn't allow you to define freight management between cargo stations, you have to use mods for that, and it still doesn't completely work, CS2 doesn't have bikes)

I still play Caesar III from time to time, it has aged very well to this day, especially thanks to Augustus/Julius mods. Maybe we just peaked decades ago.