Seven Galaxies

The Seven Galaxies were a collection of galaxies near and at the centre of the universe. (TV: Twice Upon a Time) The Kaleds believed that Skaro, which existed in the Seventh Galaxy, (PROSE: The Infinity Doctors) was the only planet capable of supporting life in all of the Seven Galaxies. (TV: Genesis of the Daleks)

They were used in a question by the Eighth Doctor, "Why in the Seven Galaxies...?" (AUDIO: Neverland) and the expression "What in the Seven Galaxies?" by Romana II (AUDIO: Zagreus) and Heff. (AUDIO: Tomb Ship)

The planet Villengard's weapon factories were known as the "Nightmare of the Seven Galaxies" (TV: Twice Upon a Time) before its destruction by the War Doctor. (COMIC: The Whole Thing's Bananas)

Behind the scenes

 * According to Is Your Dad An Evil Alien?, the Earth was "a favourite target for every alien race in the Seven Galaxies".