Domestic Long Hair is not a breed. It is the label shelters and veterinarians use for a mixed-ancestry cat with a long coat, the fluffy counterpart of the everyday Domestic Short Hair. These cats come from the general cat population rather than from any pedigreed breed, so they show up in every color and pattern, from tabby and calico to solid black, smoke and bicolor. Some look much like a Maine Coon or Persian without sharing that ancestry.
Because there is no breed standard, size, coat texture and personality vary from cat to cat. What they share is a coat that needs regular brushing to prevent mats and hairballs, and the broad genetic diversity that tends to keep mixed cats healthy. Meeting an individual cat tells adopters far more than the label.