The crypt houses tombs for all deceased members of House Stark, though traditionally statues were only made for Kings in the North and Lords of Winterfell. Lord Eddard "Ned" Stark is the one who broke said tradition, creating statues of his deceased siblings after Robert's Rebellion. Though we've only seen one level on the show — the "freshest" level that houses the tombs of Lord Rickard Stark, Ned, Brandon, and Lyanna — we have no doubt that it's just as vast as in the novels.