Fairies are very small winged humanoids with pointed ears.
In Dragon Ball Z Gaiden: Shin Saiyajin Zetsumetsu Keikaku - Uchū-Hen, Goku meets a fairy while on a planet looking for a Crystal Ball which would allow him to pass the Dark Planet's magnetic protections. She is stuck in one of the many Crystal Balls he finds, and he frees her by transforming into a Super Saiyan and breaking the Crystal Ball. Later, the fairy helps Goku while he is fighting Giant Form Hatchiyack on the Dark Planet. She shows him the way to Hatchiyack's core inside his body.