With the amount of costumes he has now worn, we are primed for a ranking of Batman's comic book costumes. As a note on structure, we're only talking costumes he's worn in the "main" continuity, so no alternate reality costumes or possible future costumes. Also, no temporary one-off costumes, but we will count costumes worn by other people who have filled in for Bruce Wayne as Batman.
The informal name "Batman family" is used for a group of characters closely allied with Batman, generally masked vigilantes who either have been trained by Batman or operate in Gotham City with his tacit approval. They include: Barbara Gordon, Commissioner Gordon's daughter, who has fought crime under the vigilante identity of Batgirl and, during a period in which she was confined to a wheelchair due to a gunshot wound inflicted by the Joker, the computer hacker Oracle; Helena Bertinelli, the sole surviving member of a mob family turned vigilante, who has worked with Batman on occasion, primarily as the Huntress and as Batgirl for a brief stint; Cassandra Cain, the daughter of professional assassins David Cain, and Lady Shiva, who succeeded Bertinelli as Batgirl.
Harley Quinn: Best known as "The Joker's Girlfriend", Harley has had occasional romantic encounters with Batman, most notably her kiss with him in the episode Harley's Holiday from Batman: The Animated Series. Recently, in the The New 52, there have been a couple of stories in which Harley became infatuated either with Bruce Wayne or Batman. These attractions appear to be entirely one-sided and Batman has shown no signs of attraction towards Harley.