Gnomes were mythical creatures.
Gnomes were among the creatures depicted in The True History of Planets by Reginald Tyler. (PROSE: Mad Dogs and Englishmen)
The Doctor encountered real gnomes on the planets Albert (PROSE: Grimm Reality) and Caligaris Epsilon Six. (COMIC: A Fairytale Life)
Father Christmas said that one could teach a gnome to build a wooden train, but not a games console. (AUDIO: Death in Blackpool)