A hairbrush
A hairbrush was a tool used to style hair.
In 2365, hair taken from Doctor Katherine Pulaski's hairbrush provided a sample of her original DNA. (TNG: "Unnatural Selection")
In 2368, Deanna Troi recalled using a hairbrush while attempting to find out who had invaded her memory. (TNG: "Violations")
Elani, a Drayan "girl", always had her hair brushed before she went to sleep. She mentioned this to Tuvok in 2372. (VOY: "Innocence")
In 2373, Molly O'Brien's hair was pulled by her hairbrush while Keiko O'Brien, who was possessed by a Pah-wraith, was brushing it. (DS9: "The Assignment")
In 2374, Molly's hairbrush was one of the items that her older self was given before returning through the time portal. (DS9: "Time's Orphan")
In 2376, Lyndsay Ballard mused that she wouldn't need her hairbrush anymore once her DNA had been altered to that of the Kobali. Later, Harry Kim gave it to Mezoti, who thought it was pretty. (VOY: "Ashes to Ashes")