There was a 3e feat(?) that allowed archers to make an attack against an area and whatever was in that area had to make a Reflex save or take damage; the greater the number of archers the more the damage (and the higher the DC of the save?). It's certainly possible to home-brew something like that.Just to be clear, a creature can make a ranged attack against another creature it cannot see. It just has disadvantage on the attack roll. So while the fog cloud or whatever is helpful, you're still a target.
Depending on the style of your campaign, that could be very powerful. If your party has a number of low-level hirelings who can rain arrows down on an enemy once your wizard casts fog cloud, you could ruin an opposing army's day. If you never play large-scale battle scenarios (and I don't think that's the staple of any RPG), it won't come into play.