Slytherin
From Tardis Wiki, the free Doctor Who reference
Slytherin was one of the fictional houses of the Harry Potter series. Flip Jackson likened the Gallifreyan Chapters to Hufflepuff and Slytherin. (AUDIO: Stage Fright)
When Clara Oswald pointed out to three Doctors that their meeting couldn't happen due to a fixed point in time, the Tenth Doctor said "one point to the girl from Gryffindor." The Twelfth Doctor rebuked this, saying that she was Slytherin "all the way," and that he meant it as a compliment. (COMIC: Four Doctors)
Missy considered herself a "Slytherin girl" and could see a lot of Severus Snape in herself. (PROSE: The Liar, the Glitch and the War Zone)