Sunglasses

Sunglasses, also known as shades, (TV: The Ghost Monument) were a set of dark glass lenses fitted into frames that allowed for protection against excessive light.

Sunglasses could also be worn as a disguise. The Men in Black wore sunglasses to hide their inhuman eyes, (TV: Dreamland, The Vault of Secrets), wore sunglasses after taking over Bruce's body for similar reasons, (TV: Doctor Who) and the Zalphons used sunglasses when occupying human bodies to mask the light that would emmanate from their hosts' eyes. (PROSE: Bennelong Point)

Sunglasses could be equipped with other technologies. The Eleventh Doctor had sunglasses which could function as infrared thermal imaging scanners. He used them in Cwmtaff to track Silurians, (TV: The Hungry Earth) and for a time the Twelfth Doctor used sonic sunglasses as a replacement for his lost sonic screwdriver, (TV: The Magician's Apprentice) later using them alongside his new screwdriver. (TV: The Husbands of River Song)

Multiple pictures of cats with sunglasses existed on the Internet. Andrea Quill scrolled through them during class on her iPad. (TV: For Tonight We Might Die)

Other appearances
The First Monk wore sunglasses while in ancient Egypt. (TV: The Daleks' Master Plan)

Ace wore sunglasses while playing chess with the Seventh Doctor in 1638. (TV: Silver Nemesis)

Jo Grant wore sunglasses while looking out a portal on Skybase One. (TV: The Mutants)

Sarah Jane Smith planned on bringing sunglasses on her trip to Florana. (TV: Death to the Daleks)

Fitz Kreiner wore small round sunglasses like John Lennon in San Francisco. (PROSE: Unnatural History)

Christina de Souza wore sunglasses while on San Helios while the Tenth Doctor used his sonic screwdriver to convert his regular "brainy specs" into sunglasses. (TV: Planet of the Dead)

The Tenth Doctor wore sunglasses when he visited the Ood Sphere. (TV: The End of Time)

When he once left his sonic sunglasses in the TARDIS, the Twelfth Doctor "borrowed" a pair of Audrey Hepburn's. (PROSE: Mission of the KaaDok) The Thirteenth Doctor later lent these glasses to Graham O'Brien while on Desolation, (TV: The Ghost Monument) before returning them to Hepburn. (PROSE: Mission of the KaaDok)