Imps are invisible creatures that serve the most skillful witches. Queen Zixi summoned imps to weave an exact likeness of the Magic Cloak originally woven by Fairies. (Queen Zixi of Ix)

Sound Imps are immortal creatures whose duty is to swiftly carry all the sounds that are made. (The Life and Adventures of Santa Claus)

Ozma encountered a trio of visible imps named Olite, Udent, and Ertinent, who who had no respect for anyone or anything. They jeered at strangers and made faces at them, and often they pushed travelers out of the path or threw stones at them. Finally the Wizard came to her rescue and turned them into buttons. ("Ozma and the Little Wizard")

Tottenhots have been referred to as imps, but are not necessarily the same species. (The Patchwork Girl of Oz)

The Ruby Imps are antagonists in The Laughing Dragon of Oz.