Sarkovian

The Sarkovians were a species that the Doctor was familiar with.

When the Eleventh Doctor examined a Krovian memory-stealing device, he speculated that it may have been Sarkovian technology. (COMIC: Fooled)

The Twelfth Doctor once told Clara Oswald that he had "faced oblivion at the hands of the Sarkovian War Splinter". (COMIC: Selfie)

The Twelfth Doctor later told Hattie Munroe that he could show her a flotilla of Sarkovian Nightships. (COMIC: Playing House)