When I was growing up in Pittsburgh there were a lot of carp tournaments. Most folks fished some type of doughball but at some point someone figured out that big carp loved crayfish when their shells were soft (molting). That was the bait that one pretty much every week. It is a challenge to find softshells of course so folks would have one or two precious baits. Sometimes a bass or a bowfin would take the bait and folks would get so mad. Hard shelled (normal) crayfish worked too, but just not as well.
Another thing we used to do was fish the rivers quite a bit, mostly targeting catfish. The two baits of choice were chicken livers and kielbasa. While by and large we mostly caught catfish we still caught a fair amount of carp on those two baits.