imp

cutup, larker, madcap, skylarker

ragamuffin

brat, disrupter, misbehaver, nuisance

juvenile delinquent

gamin, gamine

hag [archaic], lamia, vampire

incubus, nightmare, succubus

afreet (or afrit), genie, jinni (or jinn)

apparition, banshee, bogey (also bogie), bugbear, familiar, familiar spirit, genius, phantasm (also fantasm), phantom, poltergeist, shade, shadow, specter (or spectre), spirit, spook, vision, wraith

brownie, dwarf, elf, faerie (also faery), fairy, fay, gnome, goblin, gremlin, hobgoblin, kobold, leprechaun, pixie (also pixy), puck, sprite, troll

monster, ogre