The books reveal that Mrs. Figg is a squib (a person born to at least one magical parent, but is unable to produce magic) and that she is also an original member of The Order of the Phoenix.
Mrs. Figg babysat Harry every year on Dudley’s birthday, often boring him with pictures of her cats (part-kneazles). In the films she is portrayed as a kind and simple person, but in the books she comes off more bitter, and purposefully makes Harry dislike her so that the Dursleys will continue to allow her to keep an eye on him. “I was to keep an eye on you but not say anything. You were too young,” she told him. “I’m sorry I gave you such a miserable time, Harry, but the Dursleys would never have let you come if they’d thought you enjoyed it. It wasn’t easy, you know … ”
In the film version of Order of the Phoenix, Mrs. Figg lives on Privet Drive, while in the books she lives on Wisteria Walk. She’s often overlooked as one of the bravest characters in the series. Fans of the character on reddit started a thread praising Mrs. Figg for her bravery in joining the Order and defending Harry for years despite her inability to use magic. It’s quite an accomplishment to take on Voldemort when, as she tells Harry, she “never so much as transfigured a teabag.”