The Conjuring Universe is one of my favorite series of horror movies.
i like it to watch the movies in their chronological sequence.

But i can also recommend "The Boy"... with this family who are looking for a nanny for their child but the the child is a doll which looks very similar to their son.
The Nanny has to struggle with some mysterious happenings and find herself a little bit.

Cloverfield Lane is also a good one. But i think more that this is a psychothriller or something like that instead a "classic" horror movie.