Socks

Socks are clothing for the feet, usually knitted or made from stretchy material.

• Dumbledore's vision in the Mirror of Erised was himself holding "a pair of thick, woolen socks" (PS12).
• On his tenth birthday, Harry received a coathanger and a pair of Uncle Vernon's old socks (PS3). In fact, the sad state of Harry's socks made Molly Weasley fuss over him even more, washing and folding his socks when he was on holiday (CS4, GF10).
• Harry tricked Lucius Malfoy by handing him a dirty sock, which Lucius threw in the air to be caught by his House-elf Dobby, making him free (CS18). From then on, socks were Dobby's favorite clothing, and he eventually owned a collection of seven, including a "foul mustard yellow" sock once belonging to Uncle Vernon in which Harry had stored his pocket sneakascope, as well as a pair of violet socks from Ron (GF23).
• Dobby knitted Harry a mis-matched pair of socks for Christmas: "The left sock was bright red and had a pattern of broomsticks upon it; the right sock was green with a pattern of Snitches" (GF23).
• Hermione learned magical knitting so she could mass-produce Elf-hats, socks and scarves in hopes of setting the Hogwarts House-elves free (OP16).