Cufflinks were a form of jewellery worn on the shirt cuffs.
The Sixth Doctor wore cat cufflinks on at least one occasion. (AUDIO: Trouble in Paradise)
Victor Klum, an Abzorbalovian, wore a pair of cufflinks whilst disguised as a human. (PROSE: The Visual Dictionary [+]Andrew Darling, Kerrie Dougherty, David John and Simon Beecroft, Dorling Kindersley (2007)., TV: Love & Monsters [+]Russell T Davies, Doctor Who series 2 (BBC One, 2006).)
Joe Buchanan wore dice cuff links, displaying his gambling tendency. (TV: The God Complex)