demon

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

bête noire, bogey (also bogie), bugaboo, bugbear, hobgoblin, ogre