I don't think we're on the same page. I can name hundreds of single player games since SWAT 4, but I don't think you're referring to just games in general since it seems you're referring to tactical shooters. In that case I'm not sure if I can name ANY tactical shooter other than ARMA. I certainly can't name any worth playing.
But for single player games in general the list is all but endless.
AKA multiplayer; where you don't have to do everything by yourself. Not that I found ARMA fun even with other people, but that's another topic altogether.