Annabelle is one of Ed and Lorraine Warren's cases. Their doll is considered the most "evil" in their paranormal collection. Allegedly it's possessed by a demon and even has a body count.
They made some shitty movies about it and tried to make the doll creepier than Raggedy Ann is but honestly it just made it comical. All dolls are creepy, you don't have to try. But those movies went way downhill after the second Conjuring. Like, The Nun was just boring and La Llorona was just sad nonsense. It got some of the folklore right, but you can do better than that.